Humidifier with passive humidifying capability adjusting function

Abstract

The humidifier with the passive humidifying capacity adjusting function comprises a humidifying assembly, the axial end of the humidifying assembly is connected with an air inlet end cover, the other end of the humidifying assembly is connected with an exhaust end cover, the humidifying assembly comprises a humidifying shell, a plurality of membrane assemblies and a plurality of bypass assemblies are arranged in the humidifying shell, and each bypass assembly comprises a bypass pipe. One end of the bypass pipe is connected with the dry-side air inlet cavity, the other side of the bypass pipe is connected with the dry-side air outlet cavity, a bypass one-way valve is arranged in the bypass pipe, and the opening pressure of the bypass one-way valve is matched with the current density, needing to reduce the humidifying amount, of the galvanic pile. The bypass one-way valve is automatically matched with the opening or closing state in the change of the gas inlet pressure, so that the gas completely entering the electric pile is humidified under the working condition of low current density, and a part of gas is automatically bypassed to enter the electric pile without being humidified under the condition of high current density; and the requirement that the humidifying degree of the humidifier is matched with the working condition of the electric pile is met with a simplified structure and relatively low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and particularly to the humidification technology of hydrogen fuel cells. Background Art

[0002] Hydrogen fuel cells are an important direction for future clean energy. As one of the key components of the fuel cell system, the humidifier ensures that the proton exchange membrane of the stack is in an efficient working state by humidifying the incoming air, thereby achieving the high efficiency and long life of the stack.

[0003] Currently, the commonly used membrane humidifier is in a fixed humidification mode or an adjustment mode that requires the control of the stack system. Among them, the fixed humidification mode cannot adjust the humidification capacity according to the operating conditions of the stack system. The adjustment mode controlled by the stack system not only requires the calibration of the operating conditions of the stack system, but also requires adding a control system, solenoid valves, and writing relevant programs in the stack system and the humidifier, increasing the structural complexity and cost of the system and the humidifier.

[0004] In order to simplify the stack system and the humidifier and meet the market's need for low cost, the applicant organized the development of the present invention, aiming to adjust the humidification capacity of the humidifier without adding electronic control components and without writing relevant programs, so that the humidification conditions match the operating conditions of the stack system. Summary of the Invention

[0005] The purpose of the present invention is to provide a humidifier with a passive humidification capacity adjustment function, which can automatically reduce the outlet humidity of the humidifier when the current density is relatively high, and does not require adding electronic components such as sensors and controllers, nor rewriting or writing programs, to meet the need of matching the humidification degree of the humidifier with the stack conditions at a relatively low cost.

[0006] To achieve the above purpose, the humidifier with a passive humidification capacity adjustment function of the present invention includes a humidification component. One axial end of the humidification component is connected with an intake end cover, and the other axial end is connected with an exhaust end cover. The intake end cover is connected with an intake port, and the exhaust end cover is connected with an exhaust port. The intake port is used to be connected with the gas path of the stack system and introduce ambient air, and the exhaust port is used to be connected with the gas path of the stack system and send the humidified air into the stack. A dry-side intake cavity is formed between the intake end cover and the humidification component, and a dry-side outlet cavity is formed between the exhaust end cover and the humidification component. The humidification component includes a humidification housing, and several membrane components are arranged in the humidification housing. Each membrane component is respectively communicated with the dry-side intake cavity and the dry-side outlet cavity. Several bypass components are also arranged in the humidification housing. The bypass component includes a bypass pipe. One end of the bypass pipe is connected with the dry-side intake cavity and the other side is connected with the dry-side outlet cavity. A bypass check valve is arranged in the bypass pipe, and the opening pressure of the bypass check valve matches the current density at which the stack needs to reduce the humidification amount.

[0007] The inner cavity of the humidifying housing is a moisture chamber. The humidifying housing is provided with a moisture inlet and a moisture outlet. The moisture inlet is used to introduce the humid air of the moisture source, and the moisture outlet is connected to the gas path of the fuel cell stack system and is used to discharge the humid air into the atmosphere.

[0008] The membrane modules and bypass modules are collectively referred to as the flow-through components. An air inlet sealing structure is provided between one axial end of the flow-through component and the humidifying housing, and an air outlet sealing structure is provided between the other end of the flow-through component and the humidifying housing. The air inlet sealing structure and the air outlet sealing structure are symmetrically arranged; The air inlet sealing structure is used to keep the moisture chamber sealed from the dry-side air inlet chamber, and the air outlet sealing structure is used to keep the moisture chamber sealed from the dry-side air outlet chamber.

[0009] The air inlet sealing structure includes a potting adhesive layer. The air inlet sealing adhesive layer is perpendicular to the axis of the humidifying housing. The axes of the bypass modules are all parallel to the axis of the humidifying housing; each membrane module has a plurality of hollow fiber membranes, and the axes of the hollow fiber membranes are all parallel to the axis of the humidifying housing; the hollow fiber membranes of each membrane module pass through the potting adhesive layers at both axial ends thereof, and one end of each hollow fiber membrane of each membrane module communicates with the dry-side air inlet chamber and the other end communicates with the dry-side air outlet chamber; The potting adhesive layer is adhesively bonded to the humidifying housing in the circumferential direction. The outer surface of the potting adhesive layer is recessed with an annular groove at the outer axial end. The annular groove and the humidifying housing enclose a U-shaped groove, and a caulking agent is poured or smeared in the U-shaped groove to form an annular caulking structure; The air inlet end cover and the exhaust end cover are collectively referred to as the outer end cover. A dry-wet sealing ring is installed between the humidifying housing and the outer end cover before the caulking structure is cured. After the caulking structure is cured, the dry-wet sealing ring, the potting adhesive layer and the humidifying housing are adhesively bonded together to form the air inlet sealing structure.

[0010] Each membrane module and the hollow fiber membranes are all installed in a membrane cartridge. The membrane cartridge includes an upper half cartridge and a lower half cartridge. The upper half cartridge and the lower half cartridge are connected by a snap structure to form a complete membrane cartridge; a plurality of air inlet windows for allowing the humid air to enter the membrane cartridge are provided on the membrane cartridge opposite to the moisture inlet, and n1 air inlet windows are provided on the membrane cartridge; a plurality of air outlet windows for allowing the humid air that has undergone heat and moisture exchange to flow out of the membrane cartridge are provided on the membrane cartridge opposite to the moisture outlet, and n2 air outlet windows are provided on the membrane cartridge; n1≥n2.

[0011] The bypass check valve includes an annular valve seat, and the outer circumferential surface of the valve seat is in interference fit with the inner wall of the bypass pipe; A valve core is slidably inserted into the valve seat. With the air flow direction as the forward direction, the front end of the valve core extends forward out of the valve seat, the rear end of the valve core is located behind the valve seat, a ring-shaped platform is radially protruded at the rear end of the valve core, and a spring is sleeved on the valve core between the ring-shaped platform and the valve seat; an annular groove is provided on the outer surface of the front end of the valve core, and an O-ring is embedded in the annular groove. The O-ring forms a compression seal with the valve seat under the pressing force of the spring; a plurality of air vents are provided along the circumferential direction in the middle and rear parts of the valve core, and when the O-ring is pressed against the valve seat by the spring force, all the air vents are located behind the valve seat.

[0012] A positioning step is provided on the inner wall of the bypass pipe, and the valve seat is tightly pressed forward at the positioning step; a diaphragm positioning ring and a diaphragm buckle part are provided at intervals in the middle of the diaphragm box, and an outer shell buckle part adapted to the diaphragm buckle part and an outer shell positioning ring adapted to the diaphragm positioning ring are provided on the inner wall of the humidifying outer shell; a bypass positioning ring corresponding to the outer shell positioning ring is provided on the outer wall of the bypass pipe. Research and development description: Under the condition of low current density, the heat generated by the stack is less, and the proton exchange membrane (PEM) is prone to becoming dry due to lack of sufficient heat. At this time, the requirement for humidification is relatively high, and the humidity of the proton exchange membrane is maintained by a higher air humidity to ensure the efficiency of proton conduction and the performance of the stack.

[0013] Under the condition of high current density, the electrochemical reaction rate inside the stack accelerates, and the heat generation increases significantly. At this time, the proton exchange membrane is more likely to maintain a wet state, and there may even be a risk of excessive wetness. Therefore, when the current density is high, the demand for air humidity decreases to avoid performance degradation caused by excessive wetness.

[0014] The design idea of the present invention is to set a bypass component in addition to the normal membrane component for humidification in the humidifier; the membrane component always maintains the humidification effect on the air entering the stack during operation, while the bypass component is usually disconnected in the system and thus does not function. When the current density is high, the bypass check valve automatically opens and is automatically connected to the system to divert a part of the gas for entering the stack, and this part of the gas is sent to the stack without being humidified by the membrane component, thereby avoiding excessive humidity of the proton exchange membrane.

[0015] The present invention improves the technical route by using the principle of parameter correlation. The principle of parameter correlation means that the higher the current density of the stack, the greater the intake air volume of the system, and the higher the intake air pressure (the force received by the bypass check valve). The present invention changes the technical route of monitoring the current density or power to determine when to reduce the humidification amount to the technical route of determining when to reduce the humidification amount through the intake air pressure of the humidifier, so that it is not necessary to monitor the current density and it is not necessary to add a solenoid valve, and the need for the humidification degree of the humidifier to match the stack working conditions can be met at low cost.

[0016] The present invention has the following advantages: The structure of the present invention is simple and the cost is relatively low. There is no need to add electronic components such as temperature sensors, current sensors, and solenoid valves, and there is no need to write programs. The bypass check valve automatically matches the open or closed state according to the change of the intake pressure, which not only ensures humidification of all the gases entering the fuel cell stack under low current density conditions, but also automatically bypasses a part of the gases without humidification and enters the fuel cell stack under high current density conditions, meeting the need of the humidifier to match the humidification degree with the fuel cell stack working conditions with a simplified structure and relatively low cost.

[0017] In the present invention, the opening pressure of the bypass check valve can be adjusted by using springs with different elastic forces. The specific opening pressure is determined by the designer through actual experiments for a specific fuel cell stack system (it is found through experiments that the intake pressure at which the humidification amount needs to be reduced also corresponds to the current density at which the humidification amount needs to be reduced). That is, to implement the present invention, the designer needs to conduct experiments on a specific fuel cell stack system to determine the current density at which the humidification amount needs to be reduced for the specific fuel cell stack and the corresponding intake pressure at this current density, so as to determine the opening pressure of the bypass check valve.

[0018] The specific structure of the intake air sealing structure in the present invention determines its stable and long-lasting sealing performance. During the use of the humidifier, the moisture has little effect on the caulking structure, so the caulking agent is not easily aged. Install a dry-wet sealing ring between the humidification outer shell and the outer end cover before the caulking structure cures, so that the dry-wet sealing ring can also play a technical role in preventing the caulking agent from overflowing, and carry out the next process when the caulking agent is not completely cured, thus improving the production efficiency.

[0019] The upper half box and the lower half box are connected by a buckle structure, which is convenient for arranging the upper half box and the lower half box around the outside after positioning each hollow fiber membrane. After the two are buckled, a complete membrane module is formed. n1≥n2 can make the wet air fully distributed, optimize the heat and moisture exchange efficiency, avoid the accumulation of wet air, maintain the system pressure balance, and maintain the stability and economy of the system while ensuring the heat and moisture exchange efficiency.

[0020] The bypass check valve has a simple structure, is convenient to be installed and positioned in the pipe, and is convenient to adapt to different opening pressures by adjusting the spring elastic force. The O-ring forms a press-fit seal with the valve seat under the pressing force of the spring, ensuring that the bypass check valve is closed during normal operation so that the bypass component does not bypass the air flow. When the intake pressure overcomes the spring elastic force, the valve core can move forward, connecting each vent port to the space on both sides of the valve seat, thus opening the bypass check valve.

[0021] The positioning step makes the installation position of the bypass check valve unified and also makes the bypass check valve more firmly installed. The settings of the membrane box buckle part and the membrane box positioning ring enable each membrane component to be more conveniently and firmly positioned. The bypass positioning ring facilitates the positioning of the bypass component. Both the bypass positioning ring and the membrane box positioning ring correspond to the housing positioning ring, eliminating the need to set two positioning rings on the inner wall of the humidifying housing corresponding to the bypass positioning ring and the membrane box positioning ring, avoiding possible structural interference caused by setting two positioning rings on the inner wall of the humidifying housing, and also making the assembly operation more orderly and unified. Brief Description of the Drawings

[0022] Figure 1 is a three-dimensional structural schematic diagram of the present invention.

[0023] Figure 2 is a sectional structural schematic diagram of the present invention.

[0024] Figure 3 is Figure 2 an enlarged view of part A in

[0025] Figure 4 is a structural schematic diagram of the humidifying component after removing the humidifying housing.

[0026] Figure 5 is a sectional structural schematic diagram of the membrane component.

[0027] Figure 6 is an enlarged structural schematic diagram of the buckle connection part between the upper half box and the lower half box.

[0028] Figure 7 is a structural schematic diagram of the bypass component.

[0029] Figure 8 is Figure 7 an enlarged view of part B in Detailed Description of the Preferred Embodiment

[0030] As Figures 1 to 8 shown, the humidifier with the function of passive humidification capacity adjustment of the present invention includes a humidifying component 1. One axial end of the humidifying component 1 is connected with an air inlet end cover 2, and the other axial end of the humidifying component 1 is connected with an air outlet end cover 3. The air inlet end cover 2 is connected with an air inlet 4, and the air outlet end cover 3 is connected with an air outlet 5. The air inlet 4 is used to be connected with the gas path of the fuel cell system and introduce ambient air, and the air outlet 5 is used to be connected with the gas path of the fuel cell system and send the humidified air into the fuel cell. A dry-side air inlet cavity 6 is formed between the air inlet end cover 2 and the humidifying component 1, and a dry-side air outlet cavity 7 is formed between the air outlet end cover 3 and the humidifying component 1. The humidifying component 1 includes a humidifying housing 8, and a plurality of membrane components 9 are arranged in the humidifying housing 8. Each membrane component 9 is respectively communicated with the dry-side air inlet cavity 6 and the dry-side air outlet cavity 7; The humidifying housing 8 is also provided with a plurality of bypass components. The bypass components include a bypass pipe 10. One end of the bypass pipe 10 is connected to the dry-side intake cavity 6 and the other side is connected to the dry-side outlet cavity 7. A bypass check valve 11 is arranged in the bypass pipe 10, and the opening pressure of the bypass check valve 11 is matched with the current density at which the fuel cell stack needs to reduce the humidification amount.

[0031] The inner cavity of the humidifying housing 8 is a moisture cavity. The humidifying housing 8 is provided with a moisture inlet 12 and a moisture outlet 13. The moisture inlet 12 is used to introduce the humid air of the moisture source, and the moisture outlet 13 is connected to the gas path of the fuel cell stack system and is used to discharge the humid air into the atmosphere.

[0032] The membrane modules 9 and the bypass components are collectively referred to as the flow-through components. An intake sealing structure is arranged between one axial end of the flow-through components and the humidifying housing 8, and an outlet sealing structure is arranged between the other end of the flow-through components and the humidifying housing 8. The intake sealing structure and the outlet sealing structure are symmetrically arranged, and the intake end cover 2 and the exhaust end cover 3 are symmetrically arranged; due to the symmetrical arrangement of the intake sealing structure and the outlet sealing structure, only the intake sealing structure will be described in detail in the present invention, and the outlet sealing structure will not be elaborated.

[0033] The intake sealing structure is used to keep the moisture cavity sealed from the dry-side intake cavity 6, and the outlet sealing structure is used to keep the moisture cavity sealed from the dry-side outlet cavity 7.

[0034] The intake sealing structure includes a potting adhesive layer 14. The intake sealing adhesive layer is perpendicular to the axis of the humidifying housing 8, and the axes of the bypass components are all parallel to the axis of the humidifying housing 8; each membrane module 9 has a plurality of hollow fiber membranes 15, and the axes of the hollow fiber membranes 15 are all parallel to the axis of the humidifying housing 8; each hollow fiber membrane 15 of each membrane module 9 passes through the potting adhesive layer 14 at both axial ends thereof, and one end of each hollow fiber membrane 15 of each membrane module 9 communicates with the dry-side intake cavity 6 and the other end communicates with the dry-side outlet cavity 7; The potting adhesive layer 14 is adhesively bonded to the humidifying housing 8 in the circumferential direction. The outer surface of the potting adhesive layer 14 is recessed with an annular groove at the outer axial end, and the annular groove and the humidifying housing 8 enclose a U-shaped groove. A caulking agent is poured or applied in the U-shaped groove to form an annular caulking structure 16; The intake end cover 2 and the exhaust end cover 3 are collectively referred to as the outer end cover. A dry-wet sealing ring 17 is installed between the humidifying housing 8 and the outer end cover before the caulking structure 16 is cured. After the caulking structure 16 is cured, the dry-wet sealing ring 17, the potting adhesive layer 14 and the humidifying housing 8 are adhesively bonded together to form the intake sealing structure.

[0035] The specific structure of the intake air sealing structure in the present invention determines that it has a stable and long-lasting sealing performance. During the use of the humidifier, moisture has little impact on the caulking structure 16, so the caulking agent is not easily aged. Before the caulking structure 16 is cured, a dry-wet sealing ring 17 is installed between the humidification housing 8 and the outer end cover, so that the dry-wet sealing ring 17 can also play a technical role in preventing the caulking agent from overflowing. The next process is carried out in the state where the caulking agent is not completely cured, thereby improving the production efficiency.

[0036] Each membrane module 9 and the hollow fiber membrane 15 are both installed in a membrane cartridge. The membrane cartridge includes an upper half cartridge 18 and a lower half cartridge 19. The upper half cartridge 18 and the lower half cartridge 19 are connected by a snap structure 20 to form a complete membrane cartridge. A plurality of intake windows 30 for allowing humid air to enter the membrane cartridge are provided on the membrane cartridge opposite to the moisture inlet 12. There are n1 intake windows 30 on the membrane cartridge. A plurality of outlet windows 31 for allowing the humid air that has undergone heat and moisture exchange to flow out of the membrane cartridge are provided on the membrane cartridge opposite to the moisture outlet 13. There are n2 outlet windows 31 on the membrane cartridge. n1≥n2.

[0037] The upper half cartridge 18 and the lower half cartridge 19 are connected by a snap structure 20, which is convenient for arranging the upper half cartridge 18 and the lower half cartridge 19 around the outside after positioning each hollow fiber membrane 15, and forming a complete membrane module 9 after snapping the two. n1≥n2 can make the humid air fully distributed, optimize the heat and moisture exchange efficiency, avoid the accumulation of humid air, maintain the system pressure balance, and maintain the stability and economy of the system while ensuring the heat and moisture exchange efficiency.

[0038] The bypass check valve 11 includes an annular valve seat 21, and the outer circumferential surface of the valve seat 21 is in interference fit with the inner wall of the bypass pipe 10; A valve core 22 is slidably inserted into the valve seat 21. Taking the air flow direction as the forward direction, the front end of the valve core 22 extends forward out of the valve seat 21, the rear end of the valve core 22 is located behind the valve core 22, and an annular platform 23 is radially protruded at the rear end of the valve core 22. A spring 24 is sleeved on the valve core 22 between the annular platform 23 and the valve seat 21; the spring 24 presses the valve seat 21 forward and presses the annular platform 23 backward.

[0039] An annular groove is provided on the outer surface of the front end portion of the valve core 22, and an O-ring 25 is embedded in the annular groove. The O-ring 25 forms a press-fit seal with the valve seat 21 under the pressing force of the spring 24; a plurality of air vents are provided on the middle and rear portions of the valve core 22 along the circumferential direction, and each air vent is located behind the valve seat 21 in the state where the O-ring 25 is press-fitted with the valve seat 21 under the elastic force of the spring 24.

[0040] The bypass check valve 11 has a simple structure, which is convenient for installation and positioning in the pipe, and it is convenient to adapt to different opening pressures by adjusting the elastic force of the spring 24. The O-ring 25 forms a press-fit seal with the valve seat 21 under the pressing force of the spring 24, ensuring that the bypass check valve 11 is closed during normal operation, so that the bypass component does not bypass the air flow. After the intake pressure overcomes the elastic force of the spring 24, the valve core 22 can move forward, connecting each air vent to the space on both sides of the valve seat 21, thus opening the bypass check valve 11.

[0041] The inner wall of the bypass pipe 10 is provided with a positioning step 26, and the valve seat 21 is tightly pressed forward at the positioning step 26; the middle part of the diaphragm box is provided with a diaphragm box positioning ring 27 and a diaphragm box buckle part 28 at intervals, and the inner wall of the humidifying housing 8 is provided with a housing buckle part adapted to the diaphragm box buckle part 28 and a housing positioning ring adapted to the diaphragm box positioning ring 27; a bypass positioning ring 29 is provided on the outer wall of the bypass pipe 10 corresponding to the housing positioning ring.

[0042] The positioning step 26 unifies the installation position of the bypass check valve 11 and also makes the bypass check valve 11 more firmly installed. The settings of the diaphragm box buckle part 28 and the diaphragm box positioning ring 27 make it more convenient and firm to position each diaphragm component 9. The bypass positioning ring 29 facilitates the positioning of the bypass component. The bypass positioning ring 29 and the diaphragm box positioning ring 27 both correspond to the housing positioning ring, eliminating the need to provide two positioning rings on the inner wall of the humidifying housing 8 corresponding to the bypass positioning ring 29 and the diaphragm box positioning ring 27, avoiding possible structural interference caused by the two positioning rings provided on the inner wall of the humidifying housing 8 and making the assembly operation more orderly and unified.

[0043] During use, the present invention is installed at the fuel cell system of a hydrogen energy vehicle. The intake port 4 communicates with the ambient air through the gas path of the fuel cell system, and the exhaust port 5 communicates with the fuel cell through the gas path of the fuel cell system and supplies fresh air (oxygen) to the fuel cell to support the fuel cell in performing an electrochemical reaction. The humid air inlet 12 introduces high-temperature air. After the fuel cell performs an electrochemical reaction, high-humidity gas is formed on the cathode side. Therefore, the humid air source can adopt the gas on the cathode side of the fuel cell, and of course, a separate humidifier can also be used to form a high-humidity air source. The humid air outlet 13 finally discharges into the atmosphere through the tail gas discharge port after passing through the gas path of the fuel cell system.

[0044] During normal operation (when the current density of the fuel cell stack is moderate or low), the fuel cell stack requires less intake air, and the intake pressure of the gas path of the fuel cell stack system is low. Therefore, the bypass check valve 11 is closed, and all the intake air (dry-side gas) passes through the membrane module 9. When the intake air (dry-side gas) passes through each hollow fiber membrane 15, it undergoes heat and moisture exchange with the highly humid gas outside the hollow fiber membrane 15 (the moisture in the moisture chamber enters the membrane cartridge through multiple intake windows 30 and is located outside the hollow fiber membrane 15). The humidified intake air (dry-side gas) inside the hollow fiber membrane 15 is sent to the fuel cell stack through the dry-side outlet chamber 7 and the exhaust port 5 to support the fuel cell stack in performing an electrochemical reaction. The dehumidified wet gas outside the hollow fiber membrane 15 enters the moisture chamber through multiple outlet windows 31, and then is discharged to the gas path of the fuel cell stack system through the moisture outlet 13, and is finally discharged into the atmosphere through the tail gas emission port after being processed.

[0045] When the current density of the fuel cell stack is higher than the predetermined value determined by the designer through experiments, resulting in the intake pressure being higher than the opening pressure of the bypass check valve 11, the spring 24 is compressed, and the valve core 22 moves forward to open the bypass check valve 11. At this time, a part of the gas in the dry-side intake chamber 6 is shunted, and instead of being humidified by the membrane module 9, it is directly bypassed to the dry-side outlet chamber 7 through the bypass assembly, reducing the humidity of the gas supplied to the fuel cell stack, thereby avoiding a decrease in performance caused by excessive gas humidity when the fuel cell stack is in a high current density condition (such as the PEM being flooded with water, a decrease in proton conductivity, a decrease in mechanical properties, an obstruction in oxygen transmission, incomplete reaction, an increase in energy consumption, etc.).

[0046] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims

1. A humidifier with a passive humidification capacity adjustment function, comprising a humidification component, wherein an air inlet end cap is connected to one axial end of the humidification component, an exhaust end cap is connected to the other axial end of the humidification component, the air inlet end cap is connected to an air inlet port, and the exhaust end cap is connected to an exhaust port; the air inlet port is used to connect to the gas path of the battery stack system and introduce ambient air, and the exhaust port is used to connect to the gas path of the battery stack system and send the humidified air into the battery stack; a dry side air inlet cavity is formed between the air inlet end cap and the humidification component, and a dry side air outlet cavity is formed between the exhaust end cap and the humidification component; the humidification component comprises a humidification housing, and a plurality of membrane assemblies are arranged in the humidification housing, and each membrane assembly is connected to the dry side air inlet cavity and the dry side air outlet cavity respectively; Features: A plurality of bypass components are also provided in the humidification shell. The bypass components include a bypass pipe. One end of the bypass pipe is connected to the dry side air inlet cavity and the other end is connected to the dry side air outlet cavity. A bypass check valve is provided in the bypass pipe. The opening pressure of the bypass check valve matches the current density of the fuel cell stack that needs to reduce the humidification amount.

2. The humidifier with passive humidification capacity adjustment function according to claim 1, characterized in that: The inner cavity of the humidifying shell is a moisture cavity, and the humidifying shell is provided with a moisture inlet and a moisture outlet. The moisture inlet is used to introduce humid air from a moisture source, and the moisture outlet is connected to the gas path of the fuel cell stack system and is used to discharge the humid air into the atmosphere.

3. The humidifier with passive humidification capacity adjustment function according to claim 2, characterized in that: Each membrane assembly and each bypass assembly is collectively referred to as a flow assembly, an air inlet sealing structure is provided between one axial end of the flow assembly and the humidification housing, an air outlet sealing structure is provided between the other end of the flow assembly and the humidification housing, and the air inlet sealing structure and the air outlet sealing structure are symmetrically arranged; The air inlet sealing structure is used to keep the wet air cavity and the dry side air inlet cavity sealed, and the air outlet sealing structure is used to keep the wet air cavity and the dry side air outlet cavity sealed.

4. The humidifier with passive humidification capacity adjustment function according to claim 3, characterized in that: The air inlet sealing structure includes a potting rubber layer, the air inlet sealing rubber layer is perpendicular to the axis of the humidifier housing, and the axis of each bypass assembly is parallel to the axis of the humidifier housing; each membrane assembly has a plurality of hollow fiber membranes, and the axis of each hollow fiber membrane is parallel to the axis of the humidifier housing; each hollow fiber membrane of each membrane assembly passes through the potting rubber layer at both ends of the axial direction, and one end of each hollow fiber membrane of each membrane assembly is communicated with the dry side air inlet cavity and the other end is communicated with the dry side air outlet cavity; The potting glue layer is bonded to the humidifier shell in the circumferential direction, and the outer surface of the potting glue layer is recessed at the axial outer end to form an annular groove, and the annular groove and the humidifier shell form a U-shaped groove, and a caulking agent is poured or applied in the U-shaped groove to form an annular caulking structure; The air intake end cover and the exhaust end cover are collectively referred to as the outer end cover. Before the caulking structure is cured, a dry-wet sealing ring is installed between the humidifying shell and the outer end cover. After the caulking structure is cured, the dry-wet sealing ring, the potting glue layer and the humidifying shell are bonded together to form an air intake sealing structure.

5. The humidifier with passive humidification capacity adjustment function according to claim 4, characterized in that: Each membrane assembly and hollow fiber membrane are installed in a membrane box, which includes an upper half box and a lower half box, which are connected to each other through a snap-fit ​​structure to form a complete membrane box; a plurality of air inlet windows for allowing moist air to pass into the membrane box are provided on the membrane box opposite to the moisture inlet, and n1 air inlet windows are provided on the membrane box; a plurality of air outlet windows for allowing moist air that has undergone moisture heat exchange to flow out of the membrane box are provided on the membrane box opposite to the moisture outlet, and n2 air outlet windows are provided on the membrane box; n1≥n2.

6. The humidifier with passive humidification capacity adjustment function according to claim 1, characterized in that: The bypass check valve comprises an annular valve seat, the circumferential outer surface of the valve seat is interference fit with the inner wall of the bypass pipe; A valve core is slidably inserted in the valve seat. With the airflow direction as the forward direction, the front end of the valve core extends forward of the valve seat, and the rear end of the valve core is located behind the valve core. The rear end of the valve core is radially protruded with an annular platform, and a spring is sleeved on the valve core between the annular platform and the valve seat; an annular groove is provided on the outer surface of the front end of the valve core, and an O-ring is embedded in the annular groove. The O-ring forms a crimping seal with the valve seat under the tight pressure of the spring; a plurality of vents are circumferentially provided at the middle and rear part of the valve core, and each vent is located behind the valve seat when the O-ring is crimped with the valve seat under the elastic force of the spring.

7. The humidifier with passive humidification capacity adjustment function according to claim 6, characterized in that: A positioning step is provided on the inner wall of the bypass pipe, and the valve seat is pressed forward against the positioning step; a membrane box positioning ring and a membrane box buckle portion are provided at intervals in the middle of the membrane box, and a shell buckle portion matched with the membrane box buckle portion and a shell positioning ring matched with the membrane box positioning ring are provided on the inner wall of the humidifier shell; a bypass positioning ring is provided on the outer wall of the bypass pipe corresponding to the shell positioning ring.

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