A humidifying device for a fuel cell and a parameter control method thereof

Abstract

The present invention discloses a humidifying device for a fuel cell and a parameter control method thereof. The humidifying device includes a gas management unit, a humidifier, a temperature control unit and a water supply and drainage unit. The gas management unit includes a dry gas pipeline and an outlet pipeline. The dry gas pipeline is configured to transport and control the gas entering the humidifier, and the outlet pipeline is configured to transport and control the humidified gas discharged from the humidifier; the temperature control unit is configured to control the temperature of the water in the humidifier; the water supply and drainage unit is configured to provide water to the humidifier or discharge excess water in the humidifier; the humidifier includes an upper tube and a lower tube, and a guide tube is provided in the lower tube to separate the space in the lower tube into a central liquid rising chamber and an annular liquid falling chamber. The fuel cell humidifying device of the present invention can fully mix the dry gas and the humidifying water by arranging a guide tube in the humidifier, and can also realize that the gas flow, relative humidity, temperature and pressure in the fuel cell humidification process can be independently controlled under different working conditions, and the humidification effect is good.

Description

Technical Field

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

[0002] Fuel cells are electrochemical reaction devices that convert chemical energy directly into electrical energy. Proton exchange membrane fuel cells are currently the most widely developed type of fuel cell. They feature high energy conversion efficiency, low operating temperature, low noise, and zero pollution. They can be used in vehicles, aerospace, stationary power plants, and underwater installations. During the operation of a proton exchange membrane fuel cell, hydrogen is introduced to the anode of the stack, and air or oxygen is introduced to the cathode. Hydrogen is reacted with the anode catalyst to generate protons and electrons. The protons, in a hydrated state, pass through the proton exchange membrane to the cathode, and the electrons travel through an external circuit to the cathode. Oxygen, reacted with the protons and electrons by the cathode catalyst, generates water and releases heat. The electrons flow from the anode to the cathode in the external circuit, generating a current that can power the load.

[0003] During the operation of a proton membrane fuel cell (PEMFC), the membrane needs to have a certain degree of hydration to improve proton conductivity. Low or no humidification will accelerate membrane degradation, while excessive water may hinder the transport of reactants. Poor hydration is not only detrimental to fuel cell performance, but also affects its lifespan. To ensure that the PEM membrane has an appropriate degree of hydration under various operating conditions, fuel cells often use external humidification methods, that is, humidifying the reactants before entering the reaction flow field to increase the humidity in the reaction field and the uniformity of the membrane humidity. Therefore, humidifiers and humidification systems have become important auxiliary components and systems that affect the performance and durability of PEMFC systems.

[0004] Fuel cells typically operate under complex conditions, with the stack current often experiencing large, high-frequency load fluctuations. These large load fluctuations mean the stack current fluctuates significantly, resulting in a wide range of reactant flow rates and, consequently, a wide range of reactant moisture content. This requires the stack's reactant humidification system to be highly adaptable to these wide-ranging flow rate fluctuations. The frequent changes in current and reactant flow rates during high-frequency load fluctuations necessitate rapid response from the fuel cell system's auxiliary humidification components and devices. Otherwise, the stack will experience a dry-wet imbalance, impacting its performance and lifespan. Furthermore, fuel cells are increasingly operating at higher pressures, requiring auxiliary humidification components and devices to possess high pressure resistance. Furthermore, due to the unique structure of the stack's gas distribution flow field and reaction zone, moisture carried by the reactants must not block the flow field and gas transmission channels. This requires the humidification system to provide humidified gas free of liquid water during both steady-state operation and dynamic load-and-load conditions. This requires excellent reliability and stability.

[0005] Currently, the main humidification methods used in proton membrane fuel cell systems include membrane humidification, spray humidification, mist humidification, and bubbling humidification. For portable or vehicle-mounted applications, membrane humidification is more conducive to reducing weight and space. For fixed applications, there are no strict space restrictions, but there is a high power requirement for humidification. In this case, gas bubbling humidification, spray humidification, or mist humidification are more suitable. However, most current bubbling humidification, spray humidification, or mist humidification devices are large in size. After the humidifier completes the humidification function, it needs to be connected to a gas-liquid separation device, which is large in size and has low gas-liquid flow stability and humidification effect. In addition, due to the different internal material selection or flow field design of the test object fuel cell stack, its temperature, humidity, and pressure requirements vary. Existing humidity control systems cannot adjust according to different application requirements, nor can they achieve independent control of gas flow, relative humidity, temperature, and pressure under different operating conditions. Summary of the Invention

[0006] In view of the above technical problems, an object of the present invention is to provide an improved humidification device for a fuel cell and a parameter control method thereof.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A humidifying device for a fuel cell includes a gas management unit, a humidifier, a temperature control unit, and a water supply and drainage unit. The gas management unit includes a dry gas pipeline and a gas outlet pipeline. The dry gas pipeline is configured to transport and control the gas entering the humidifier, and the gas outlet pipeline is configured to transport and control the humidified gas discharged from the humidifier. The temperature control unit is configured to control the temperature of water in the humidifier. The water supply and drainage unit is configured to provide water to the humidifier or drain excess water from the humidifier.

[0009] The humidifier comprises:

[0010] An upper cylinder, wherein a gas-liquid separation chamber is formed therein, the upper cylinder having a closed upper end and an open lower end, and a moisture outlet communicating with the gas-liquid separation chamber is provided on the upper cylinder;

[0011] a lower cylinder which is hollow and has an open upper end and a closed lower end;

[0012] a flow guide tube disposed in the lower tube to divide the space in the lower tube into a central liquid rise chamber and an annular liquid downcomer chamber, wherein the annular liquid downcomer chamber surrounds the central liquid rise chamber, and a first through hole is provided in the flow guide tube to connect the central liquid rise chamber and the annular liquid downcomer chamber;

[0013] The lower end of the upper cylinder and the upper end of the guide cylinder are connected and sealed, and the central liquid rising chamber and the annular liquid downcomer are located below the gas-liquid separation chamber and are both connected to the gas-liquid separation chamber.

[0014] The wet gas outlet is in communication with the gas outlet line of the gas management unit;

[0015] The humidifier further includes a dry gas inlet, which is connected to the dry gas pipeline of the guide tube and the gas management unit;

[0016] The humidifier further includes a water flow port, which is arranged on the lower cylinder and communicated with the annular downcomer cavity, and the water flow port is communicated with the temperature control unit or the water supply and drainage unit.

[0017] Preferably, the water circulation port includes a water replenishment port and a water discharge port, and the water replenishment port is located above the water discharge port; the water circulation port also includes a circulating water inlet and a circulating water outlet, and the circulating water inlet is arranged above the circulating water outlet.

[0018] Preferably, the longitudinal axis of the upper tube coincides with the longitudinal axis of the lower tube, the inner diameter of the upper tube is larger than the inner diameter of the lower tube; and the ratio of the inner diameter of the guide tube to the inner diameter of the lower tube is 0.5-0.6.

[0019] Preferably, a demister is further provided in the upper cylinder, the demister is located above the gas-liquid separation chamber, and the wet gas outlet is arranged above the demister; the demister is used to filter liquid water in the humidified gas, and the demister is a wire mesh structure.

[0020] Preferably, a gas distributor is provided in the lower tube, and the gas distributor is located below the guide tube and is arranged horizontally. The gas distributor is used to evenly disperse the gas in the humidified water; the gas distributor is connected to the dry gas inlet, and a plurality of second through holes are provided on the gas distributor to connect the dry gas inlet and the central liquid rising chamber.

[0021] Preferably, a flow controller is provided on the dry gas pipeline, and the flow controller is used to adjust the flow of the dry gas; at least one air pressure sensor is also provided on the dry gas pipeline;

[0022] The air outlet pipeline is provided with at least one air pressure sensor, at least one air temperature sensor and at least one relative humidity sensor; the air outlet pipeline is also provided with a back pressure regulating valve, which is used to control the front end pressure of the fuel cell stack; the air outlet pipeline is also provided with a heating and insulation component, which is used to control the humidified gas to a preset temperature.

[0023] Preferably, the gas management unit further includes a nitrogen purge pipeline, which is used to replace the atmosphere of the humidifier and the dry gas pipeline during the startup and shutdown of the humidifier; the gas management unit further includes an exhaust gas discharge pipeline.

[0024] Furthermore, the nitrogen purge pipeline is provided with a switch valve and a nitrogen regulating valve, the switch valve is used to control the on-off of nitrogen, and the nitrogen regulating valve is used to control the flow and pressure of nitrogen.

[0025] Preferably, the humidifying device further includes an electronic control unit, which is used for power supply, calculation and sending instructions, and the electronic control unit is electrically connected to the gas management unit, the humidifier, the temperature control unit and the water supply and drainage unit.

[0026] Preferably, the temperature control unit includes a circulating water pump, a heater and a cooler connected in sequence, and the circulating water pump is used to transport the humidifying water in the humidifier to the circulation loop; the temperature control unit includes at least two water temperature sensors.

[0027] A parameter control method for a humidifying device of a fuel cell, comprising:

[0028] S1. Obtain the real-time flow rate of dry gas. When the real-time flow rate of dry gas is greater than or equal to the preset flow rate of dry gas, jump to step S2.

[0029] S2, determining whether the difference between the real-time relative humidity value of the fuel cell humidification device and the relative humidity target value is within a preset relative humidity difference threshold range; if so, jump to step S3; if not, jump to step S4;

[0030] S3, determining whether the difference between the real-time temperature value and the target temperature value of the fuel cell humidification device is within a preset temperature difference threshold range; if so, jump to step S5; if not, jump to step S6;

[0031] S4, executing a preset relative humidity control method;

[0032] S5, determining whether the difference between the real-time air pressure value of the fuel cell humidification device and the air pressure target value is within a preset air pressure difference threshold range; if so, maintaining the state until the program ends; if not, jumping to step S7;

[0033] S6, the heating power of the heating belt of the humidifying device is adjusted in real time;

[0034] S7. The back pressure regulating valve of the humidifying device adjusts the opening duty cycle.

[0035] Preferably, the method for executing the preset relative humidity control includes:

[0036] The temperature controller of the humidifying device cooperatively controls the heating power of the heater and the cooling power of the cooler.

[0037] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0038] The fuel cell humidification device of the present invention provides a guide tube in the humidifier, so that the dry gas and humidification water come into gas-liquid contact during the process of rising in the central liquid rising chamber in the guide tube, thereby fully mixing the dry gas and humidification water; the liquid phase forms a circulation flow along the guide tube, and the upward flow distance is small. Therefore, adding the guide tube is conducive to reducing the volume of the humidifier and the entire humidification device, and also improves the stability of the gas-liquid flow in the humidifier, avoiding the problem of the liquid phase flowing upward for a long distance due to flow drag, viscous force, etc.; when the liquid level is at different heights, the upstream liquid in the central liquid rising chamber is not restricted by the height of the guide tube, and forms a circulation with the annular liquid downcomer through the first through hole, thereby realizing the recycling of humidification water and saving resources; the humidifier not only realizes the humidification function but also has a gas-liquid separation function, reducing the volume of the subsequent gas-liquid separation device and saving costs; by providing four functional units of water supply and drainage, gas management, temperature control and electronic control, the gas flow, relative humidity, temperature and pressure in the fuel cell humidification process can be independently controlled under different working conditions, and the humidification effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 is a three-dimensional schematic diagram of a fuel cell humidifier according to an embodiment of the present invention;

[0041] Figure 2 is a three-dimensional schematic diagram of a guide tube in an embodiment of the present invention;

[0042] Figure 3 Schematic diagram of the connection structure of the humidifying device of the fuel cell in an embodiment of the present invention;

[0043] Figure 4 This is a parameter control flow chart of a humidifying device for a fuel cell according to an embodiment of the present invention;

[0044] Figure 5 Schematic diagram of parameter control of a humidifying device for a fuel cell according to an embodiment of the present invention;

[0045] Figure 6Schematic diagram of the coordinated control effect of the humidification device of the fuel cell in an embodiment of the present invention;

[0046] Among them, 10, humidifier; 101, first liquid level gauge; 102, first liquid level sensor; 103, upper tube; 1031, gas-liquid separation chamber; 104, lower tube; 1041, central liquid rising chamber; 1042, annular liquid falling chamber; 105, guide tube; 1051, first through hole; 1052, support foot; 106, wet gas outlet; 107, dry gas inlet; 108, water flow outlet; 1081, water supply port; 1082, drain port; 1083, circulating water inlet; 1084, circulating water outlet; 109, demister; 1010, gas distributor; 1011, liquid level gauge port; 20, Supply and drainage unit; 21, supply water line; 210, pure water; 211, water tank; 2111, second liquid level gauge; 2112, second liquid level sensor; 212, supply water pump; 214, first pipe section; 215, second pipe section; 216, third pipe section; 2161, one-way valve; 22, drainage line; 220, discharge water; 221, fourth pipe section; 2211, switch valve; 30, gas management unit; 31, dry gas pipeline; 310, dry gas; 311, flow controller; 3111, first temperature sensor; 3112, flow sensor; 312, fifth pipe section; 313, sixth pipe section Pipe section; 3131, one-way valve; 3132, first pressure sensor; 32, nitrogen purge pipeline; 320, nitrogen; 322, seventh pipe section; 3221, regulating valve; 3222, switch valve; 33, gas outlet pipeline; 330, gas outlet from stack; 331, battery stack; 332, eighth pipe section; 3321, pressure gauge; 3322, second pressure sensor; 3323, relative humidity sensor; 3324, second temperature sensor; 3325, switch valve; 3326, third pressure sensor; 333, ninth pipe section; 3331, back pressure regulating valve; 34, exhaust gas discharge pipeline; 3 40. Exhaust; 341. Tenth pipe section; 3411. On-off valve; 40. Temperature control unit; 4001. Third water temperature sensor; 401. Circulating water pump; 402. Heater; 4021. Fourth water temperature sensor; 403. Cooler; 404. Eleventh pipe section; 4041. First water temperature sensor; 405. Twelfth pipe section; 406. Thirteenth pipe section; 407. Fourteenth pipe section; 4071. One-way valve; 4072. Second water temperature sensor; 50. Electronic control unit; 501. Power supply; 502. Controller; 503. Data logger; 504. Load; 505. Industrial computer. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings to make the advantages and features of the present invention more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0048] like Figures 1 to 3 As shown, the fuel cell humidification device in this embodiment includes a gas management unit 30, a humidifier 10, a temperature control unit 40, and a water supply and drainage unit 20. The gas management unit 30 includes a dry gas pipeline 31 and a gas outlet pipeline 33. The dry gas pipeline 31 is configured to transport and control the gas entering the humidifier 10, and the gas outlet pipeline 33 is configured to transport and control the humidified gas discharged from the humidifier. The temperature control unit 40 is configured to control the temperature of the water in the humidifier 10. The water supply and drainage unit 20 is configured to supply water to the humidifier 10 or drain excess water from the humidifier 10.

[0049] Specifically, the humidifier 10 includes an upper tube 103 and a lower tube 104, and a guide tube 105 is provided in the lower tube 104. A gas-liquid separation chamber 1031 is formed inside the upper tube 103, and the upper tube 103 has a closed upper end and an open lower end. A moisture outlet 106 connected to the gas-liquid separation chamber 1031 is provided on the upper tube 103. The moisture outlet 106 is connected to the gas outlet line 33 of the gas management unit 30. The lower tube 104 is hollow and has an open upper end and a closed lower end. By arranging the gas-liquid separation chamber 11 in the upper tube 1, the humidifier 10 has a gas-liquid separation function while realizing the humidification function, reducing the volume of the subsequent gas-liquid separation device and saving costs. In this embodiment, the humidifier 10 is preferably made of high-strength materials such as stainless steel, which has good reliability and pressure resistance.

[0050] The flow guide tube 105 is disposed within the lower tube 104 to divide the space within the lower tube 104 into a central liquid riser chamber 1041 and an annular liquid downcomer chamber 1042. The annular liquid downcomer chamber 1042 surrounds the central liquid riser chamber 1041. With the flow guide tube 105 disposed within the humidifier 10, the dry gas and humidified water come into contact with each other during their ascent within the central liquid riser chamber 1041 within the flow guide tube 105, allowing for thorough mixing of the dry gas and humidified water. The top and bottom of the flow guide tube 105 are provided with legs 1052, which are welded to the inner wall of the lower tube 104. Without the flow guide tube 105, the liquid phase flows upward for a greater distance due to flow drag and viscous forces. With the addition of the flow guide tube 105, the liquid phase forms a circular flow along the flow guide tube 105, reducing its upward flow distance. Therefore, adding the flow guide tube 105 helps reduce the volume of the humidifier 10 and improves the stability of the gas-liquid flow within the humidifier 10.

[0051] The guide tube 105 is provided with a first through hole 1051 to connect the central liquid rising chamber 1041 and the annular liquid downcomer 1042. The size, shape and density of the openings of the guide tube 105 can be set accordingly according to needs, but the mechanical strength of the guide tube must be guaranteed and the flow resistance of the fluid should not be affected. In this embodiment, it is preferred that the multiple first through holes 1051 have the same size and shape, and the first through holes 1051 are evenly distributed on the wall of the guide tube 105. The first through holes 1051 are provided on the guide tube 105 to meet the diversion function of the humidifier when the liquid level is at different heights. When the liquid level is at different heights, the upstream liquid in the central liquid rising chamber 1041 is not restricted by the height of the guide tube, and forms a circulation with the annular liquid downcomer 1042 through the first through holes 1051, thereby realizing the recycling of humidification water and saving resources.

[0052] The lower end of the upper tube 103 and the upper end of the guide tube 105 are connected and sealed. The central liquid rising chamber 1041 and the annular liquid downcomer chamber 1042 are located below the gas-liquid separation chamber 1031 and are both connected to the gas-liquid separation chamber 1031. The longitudinal axis of the upper tube 103 coincides with the longitudinal axis of the lower tube 104. The inner diameter of the upper tube 103 is larger than the inner diameter of the lower tube 104. In this embodiment, the ratio of the inner diameter of the guide tube 105 to the inner diameter of the lower tube 104 is preferably 0.5-0.6, and the circulation effect of the central liquid rising chamber 1041 and the annular liquid downcomer chamber 1042 is better. In some other embodiments, the inner diameter ratio of the guide tube 105 and the lower tube 104 can also be other values, which are not limited here.

[0053] The outer angle of the upper tube 103 and the lower tube 104 at the junction is greater than or equal to 90 degrees and less than or equal to 180 degrees. Figure 1 As shown, the outer angle at the junction of the upper and lower tubes 103 and 104 is preferably 90 degrees. This primarily serves to accommodate the outward expansion caused by inertial forces during the liquid backflow above the flow guide tube 105. The local diameter increase can mitigate turbulence caused by obstruction from the vessel wall during the outward expansion process. In other embodiments, the outer angle at the junction of the upper and lower tubes 103 and 104 can also be greater than 90 degrees. When the outer angle at the junction is 180 degrees, the inner diameter of the upper and lower tubes 103 and 104 are equal.

[0054] like Figure 1 As shown, a demister 109 is further provided in the upper cylinder 103 . The demister 109 is located above the gas-liquid separation chamber 1031 and is used to filter liquid water in the humidified gas. The demister 109 is specifically a wire mesh structure. The wet gas outlet 106 is provided above the demister 109 .

[0055] A gas distributor 1010 is provided within the lower tube 104 and is positioned horizontally below the draft tube 105. The gas distributor 1010 effectively disperses the gas in the humidified water, increasing the gas-liquid contact area and thereby enhancing the heat and mass transfer rates of the water dispersed in the gas during the humidification process, thereby improving energy efficiency.

[0056] like Figure 1 and Figure 2 As shown, the humidifier further includes a dry gas inlet 107, which is connected to the guide tube 105 and the dry gas pipeline 31 of the gas management unit 30. Specifically, the dry gas inlet 107 is connected to the gas distributor 1010, and the gas distributor 1010 is provided with a plurality of second through holes (not shown in the figure) to connect the dry gas inlet 107 with the central liquid riser chamber 1041 in the guide tube 105.

[0057] The humidifier also includes a water flow port 108, which is disposed on the lower barrel 104 and communicates with the annular downcomer chamber 1042. The water flow port 108 communicates with the temperature control unit 40 or the supply and drainage unit 20. Specifically, the water flow port 108 includes a water supply port 1081 and a drainage port 1082, with the water supply port 1081 located above the drainage port 1082. The water flow port 108 also includes a circulating water inlet 1083 and a circulating water outlet 1084, with the circulating water inlet 1083 located above the circulating water outlet 1084. The lower barrel 104 also includes a liquid level gauge port 1011, which is a connection port for installing a liquid level gauge.

[0058] The specific working principle of the humidifier 10 in this embodiment is described in detail below:

[0059] Dry gas 310 flows through dry gas inlet 107, through gas distributor 1010, and is dispersed in the humidified water in the form of bubbles. Humidified water (i.e., pure water 210) flows in through water replenishment port 1081. Dry gas 310 and pure water 210 come into contact in the central liquid riser chamber 1041 within the flow guide tube 105, engaging in heat and mass transfer. The gas absorbs a certain amount of heat and moisture from the water and rises to the gas-liquid separation chamber 1031. The gas phase in the humidified water inside the flow guide tube 105 is much greater than that outside the tube. The difference in phase holdup creates a density difference between the interior and exterior spaces of the flow guide tube 105. Simultaneously, due to the radial lift, turbulent diffusion, and wall lubrication forces acting on the fluid as it flows upward, the flow direction of the fluid within the flow guide tube 105 gradually changes as it rises. The gas phase continues to rise, while the liquid phase flows downward along the exterior of the flow guide tube 105, forming a circular flow along the wall of the flow guide tube 105. Gas (humidified gas containing water vapor, hereinafter referred to as wet gas) has a certain velocity when it leaves the liquid surface. Due to the viscous forces between the fluids, the wet gas will carry a certain amount of liquid water into the gas-liquid separation chamber 1031. This liquid water typically moves in the form of droplets along with the airflow. Within the gas-liquid separation chamber 1031, the wet gas and water droplets flow at different speeds and in different streamline directions due to gravity. The water droplets rise a certain distance before returning to the liquid surface. Larger droplets rise a shorter distance. The large molecular liquid descends under the action of gravity, and part of it descends into the annular downcomer chamber 1042 and is discharged from the circulating water outlet 1084 or the drain outlet 1082. The higher flow rate moisture carries some small water droplets to the top of the gas-liquid separation chamber 1031. A wire mesh demister 109 is set above the gas-liquid separation chamber 1031. When the moisture and liquid water droplets enter the demister 109, due to the blocking effect of the wire mesh, the fluid continuously changes its movement direction, and the entrained droplets continuously collide with the wire mesh and are retained on the net. At the same time, due to the change in gas direction, there is inertial retention of the entrained droplets. The collision retention and inertial retention work together to achieve the effect of eliminating droplets, which can effectively prevent liquid water in the gas from entering the battery stack, and finally obtain ideal moisture, which is discharged through the moisture outlet 106.

[0060] The water supply and drainage unit 20 includes a water supply line 21 and a drainage line 22. The water supply line 21 is equipped with a water tank 211, a water supply pump 212, a first pipe section 214 connecting the pure water inlet 210 and the water tank 211, a second pipe section 215 connecting the water supply pump 212 and the water tank 211, and a third pipe section 216 connecting the water supply pump 212 and the humidifier dry gas inlet 107. A one-way valve 2161 is installed on the pipe section 216. The water tank 211 is used to store a certain amount of deionized water and is equipped with a second liquid level gauge 2111 and a second liquid level sensor 2112. During operation, pure water 210 enters the water tank 211 through the first pipe section 214, is then transported by the water supply pump 212 through the second pipe section 215, and then passes through the third pipe section 216 and the one-way valve 2161 to the water supply port 1081 of the humidifier 10. The one-way valve 2161 is used to prevent the humidified water in the humidifier 10 from flowing back. The drainage path 22 is provided with a fourth pipe section 221, which is equipped with an on-off valve 2211. During the drainage process, the discharged water 220 from the humidifier 10 flows out of the device through the fourth pipe section 221, and the on-off valve 2211 controls the flow of the discharged water 220.

[0061] The dry gas pipeline 31 of the gas management unit 30 is provided with a flow controller 311, which is used to adjust the flow of dry gas. The dry gas pipeline 31 is also provided with at least one air pressure sensor. The outlet pipeline 33 is provided with at least one air pressure sensor, at least one air temperature sensor, and at least one relative humidity sensor. The outlet pipeline 33 is also provided with a back pressure regulating valve, which is used to control the front end pressure of the fuel cell stack. The outlet pipeline 33 is also provided with a heating and insulation component, which is used to control the humidified gas to be at a preset temperature, such as Figure 3 As shown, a heating tape is wrapped around the pipeline between the humidifier 10 and the battery stack 331 , and the power of the heating tape is adjustable.

[0062] The gas management unit 30 also includes a nitrogen purge line 32. This line is used to replace the atmosphere in the humidifier 10 and dry gas line 31 during startup and shutdown of the humidifier, ensuring a safe atmosphere within the humidifier. The nitrogen purge line 32 is equipped with an on / off valve for controlling the flow of nitrogen gas, and a nitrogen regulating valve for controlling nitrogen flow and pressure. The gas management unit 30 also includes an exhaust line 34.

[0063] Specifically, the dry gas pipeline 31 is equipped with a flow controller 311, a fifth pipe section 312 connecting the dry gas supply device and the flow controller, and a sixth pipe section 313 connecting the flow controller 311 and the dry gas inlet 107 of the humidifier 10. The flow controller 3111 is equipped with a first temperature sensor 3111 and a flow sensor 3112. The sixth pipe section 313 is equipped with a one-way valve 3131 and a first pressure sensor 3132. During the dry gas supply process, dry gas 310 from outside the device flows sequentially through the fifth pipe section 312, the flow controller 311, and the sixth pipe section 313 to the dry gas inlet 107 of the humidifier 10. During this process, the flow controller 311 controls the flow rate according to demand.

[0064] The nitrogen purge line 32 is provided with a seventh pipe section 322, one end of which is connected to the nitrogen supply source and the other end to the pipeline between the flow controller 311 and the one-way valve 3131. The seventh pipe section 322 is provided with a regulating valve 3221 and an on-off valve 3222. The regulating valve 3221 is used to adjust the nitrogen flow rate during the nitrogen supply process, and the on-off valve 3222 is used to control the nitrogen flow. The outlet line 33 is provided with a battery stack 331, an eighth pipe section 332 connecting the moisture outlet 106 of the humidifier 10 to the battery stack 331, and a ninth pipe section 333 connecting the battery stack 331 to the exhaust port. The eighth pipe section 332 is provided with a pressure gauge 3321, a second pressure sensor 3322, a relative humidity sensor 3323, a second temperature sensor 3324, an on-off valve 3325, and a third pressure sensor 3326. A back pressure regulating valve 3331 is provided on the ninth pipe section 333 , wherein the switch valve 3325 controls the on-off of the gas on the gas outlet pipeline 33 , and the back pressure regulating valve 3331 controls the gas pressure.

[0065] The exhaust gas pipeline 34 includes a tenth pipe section 341, one end of which is connected to the exhaust port and the other end to the second pressure sensor 3322 and relative humidity sensor 3323. An on-off valve 3411 is provided on the tenth pipe section 341 to control the flow of gas. Exhaust gas pipeline 34 is used to exhaust gas during the atmosphere replacement process during the humidification device startup and shutdown process. It is also used to bypass the battery stack in emergency situations such as overpressure and overtemperature to protect the battery stack.

[0066] The temperature control unit 40 includes a circulating water pump 401, a heater 402, a cooler 403, an eleventh pipe section 404 connecting the humidifier 10 and the circulating water pump 401, a twelfth pipe section 405 connecting the circulating water pump 401 and the heater 402, a thirteenth pipe section 406 connecting the heater 402 and the cooler 403, and a fourteenth pipe section 407 connecting the cooler 403 and the humidifier 10. A first water temperature sensor 4041 is provided on the eleventh pipe section 404, a fourth water temperature sensor 4021 is provided on the heater 402, a second water temperature sensor 4072 is provided on the fourteenth pipe section 407, and a third water temperature sensor 4001 is provided on the humidifier 10. Humidification water circulation process: The humidification water from the humidifier 10 returns to the humidifier 10 in sequence through the circulating water pump 401, the heater 402, the cooler 403 and the connecting pipe. In this process, the circulating water pump 401 provides power, and the heater 402 and the cooler 403 are used for coordinated temperature control.

[0067] The electronic control unit 50 includes a power supply 501, a controller 502, a data logger 503, a load 504, and an industrial computer 505. The power supply 501 provides voltages corresponding to the loads of the humidifier's electrical components and equipment. The controller 502 performs calculations and sends commands to the humidifier according to a specific control method. The data logger 503 collects, converts, and transmits the battery stack voltage signal in real time. The load 504 executes the controller's commands to consume the electricity generated by the battery stack. The industrial computer 505 monitors and controls data parameters.

[0068] The specific working principle of the humidifying device in this embodiment is introduced in detail below:

[0069] like Figure 4 As shown, during operation, the humidification device needs to provide wet gas with different flow rates, relative humidity, temperature and pressure according to the working conditions of the battery stack. The dry gas 310 is adjusted by the flow controller 311. When the real-time flow rate of the dry gas is greater than or equal to the preset dry gas flow rate, the dry gas enters the humidifier 10 from the dry gas inlet 107 at the bottom of the humidifier 10, passes through the humidifying water at a preset temperature, and then flows out from the wet gas outlet 106 at the top of the humidifier 10 and enters the battery stack to participate in the electrochemical reaction, and the exhaust gas is discharged from the battery stack. Specifically, the parameter control method includes:

[0070] S1. Obtain the real-time flow rate of dry gas. When the real-time flow rate of dry gas is greater than or equal to the preset flow rate of dry gas, jump to step S2.

[0071] S2, determining whether the difference between the real-time relative humidity value of the fuel cell humidification device and the relative humidity target value is within a preset relative humidity difference threshold range; if so, jump to step S3; if not, jump to step S4;

[0072] S3, determining whether the difference between the real-time temperature value and the target temperature value of the fuel cell humidification device is within a preset temperature difference threshold range; if so, jump to step S5; if not, jump to step S6;

[0073] S4, executing a preset relative humidity control method;

[0074] S5, determining whether the difference between the real-time air pressure value of the fuel cell humidification device and the air pressure target value is within a preset air pressure difference threshold range. If so, maintain the state until the program ends; if not, jump to step S7;

[0075] S6, the heating power of the heating belt of the humidification device is adjusted in real time;

[0076] S7. The back pressure regulating valve of the humidifying device adjusts the opening duty cycle.

[0077] During this process, the relative humidity and air temperature of the incoming wet gas (i.e., the humidified gas entering the stack) are simultaneously controlled by the humidifying water temperature control component and the air temperature control component, while the pressure is controlled by the stack resistance and the backpressure valve. To ensure independent control of the relative humidity, temperature, and pressure of the incoming gas, the real-time temperature of the incoming gas is linked to the power of the heating cable for proportional-integral-derivative (PID) control (hereinafter referred to as PID control). The opening of the backpressure regulating valve 3331 is also linked to the real-time pressure of the incoming gas for PID control. However, when relative humidity is affected by disturbances such as gas flow rate, air temperature, pressure, and humidifying water temperature, direct PID control based on the power of heater 402 generally results in significant hysteresis. To reduce this hysteresis, the present invention implements cascade control of the relative humidity, humidifying water temperature, and heater 402 during relative humidity control. Heater 402 power is pre-controlled significantly based on changes in humidifying water temperature, and then, based on the difference between the relative humidity and a set value, the power of heater 402 is further controlled to maintain a constant relative humidity range. Since the heater 402 generally has overshoot in the process of adjusting the humidification water temperature, a second threshold is set for the humidification water temperature. When the humidification water temperature is disturbed and exceeds the second threshold under non-steady-state conditions, the cooler 403 works. When the humidification water temperature is lower than the second threshold, the cooler 403 does not work. In this way, a large overshoot can be suppressed when the heater 402 is disturbed.

[0078] like Figure 5 As shown, the preset relative humidity control method is as follows:

[0079] Temperature controller C11 pre-controls the power of heater 402 or the adjustment amount of cooler 403 based on the real-time temperature value and the target temperature value. The control result is fed back to relative humidity controller C12 via relative humidity sensor 3323. Based on the difference between the real-time relative humidity value and the target relative humidity value, the power of heater 402 or the adjustment amount of cooler 403 is then controlled in small increments to maintain a constant relative humidity range. The process cooler 403 works in conjunction with heater 402.

[0080] Figure 6 The figure shows the coordinated control effect of the humidifier. In steady-state operation, the real-time water temperature fluctuates steadily over a certain period. When the system enters dynamic operation, the instantaneous amplitude of the real-time water temperature disturbance increases. Heater 402's power is then adjusted according to the control command, and the real-time water temperature gradually returns to a small, periodic fluctuation. When the amplitude of the real-time water temperature disturbance increases, cooler 403 is activated for coordinated control, reducing the maximum dynamic amplitude of the real-time water temperature and shortening the stabilization time.

[0081] In summary, the fuel cell humidification device of the present invention, by providing a guide tube within the humidifier, allows the dry gas and humidification water to come into gas-liquid contact during their ascent in the central riser chamber within the guide tube, thereby fully mixing the dry gas and humidification water. The liquid phase forms a circular flow along the guide tube, with a relatively short upward flow distance. Therefore, adding the guide tube helps reduce the volume of the humidifier and the entire humidification device, improves the stability of the gas-liquid flow within the humidifier, and avoids the problem of the liquid phase being subjected to flow drag, viscous forces, and other effects that cause the liquid phase to flow a relatively long distance upward. When the liquid level is at different heights, the upstream liquid in the central riser chamber is not restricted by the height of the guide tube and forms a circulation with the annular downcomer through the first through hole, thus achieving the recycling of the humidification water and saving resources. The humidifier not only achieves humidification but also has a gas-liquid separation function, reducing the volume of the subsequent gas-liquid separation device and saving costs. By providing four functional units: drainage, gas management, temperature control, and electrical control, the gas flow, relative humidity, temperature, and pressure during the fuel cell humidification process can be independently controlled under different operating conditions, achieving a good humidification effect.

[0082] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0083] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. Furthermore, terms such as "upper," "lower," "left," and "right" used in this disclosure are intended solely to describe the relative positions of the components of the disclosure as shown in the accompanying drawings.

[0084] The above embodiment is intended only to illustrate the technical concepts and features of the present invention and is a preferred embodiment. Its purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. It is not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the principles of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A humidifying device for a fuel cell, comprising a gas management unit, a humidifier, a temperature control unit and a water supply and drainage unit, characterized in that: The gas management unit includes a dry gas pipeline and an outlet gas pipeline, wherein the dry gas pipeline is configured to transport and control the gas entering the humidifier, and the outlet gas pipeline is configured to transport and control the humidified gas discharged from the humidifier; the temperature control unit is configured to control the temperature of the water in the humidifier; the water supply and drainage unit is configured to provide water to the humidifier or drain excess water in the humidifier; The humidifier comprises: An upper cylinder, wherein a gas-liquid separation chamber is formed therein, the upper cylinder having a closed upper end and an open lower end, and a moisture outlet communicating with the gas-liquid separation chamber is provided on the upper cylinder; a lower cylinder which is hollow and has an open upper end and a closed lower end; a flow guide tube disposed in the lower tube to divide the space in the lower tube into a central liquid rise chamber and an annular liquid downcomer chamber, wherein the annular liquid downcomer chamber surrounds the central liquid rise chamber, and a first through hole is provided in the flow guide tube to connect the central liquid rise chamber and the annular liquid downcomer chamber; The lower end of the upper cylinder and the upper end of the guide cylinder are connected and sealed, and the central liquid rising chamber and the annular liquid downcomer are located below the gas-liquid separation chamber and are both connected to the gas-liquid separation chamber. The wet gas outlet is in communication with the gas outlet line of the gas management unit; The humidifier further includes a dry gas inlet, which is connected to the dry gas pipeline of the guide tube and the gas management unit; The humidifier further includes a water flow port, which is arranged on the lower cylinder and communicated with the annular downcomer cavity, and the water flow port is communicated with the temperature control unit or the water supply and drainage unit.

2. The humidifying device for a fuel cell according to claim 1, wherein: The water flow port includes a water supply port and a water discharge port, and the water supply port is located above the water discharge port; the water flow port also includes a circulating water inlet and a circulating water outlet, and the circulating water inlet is arranged above the circulating water outlet.

3. The humidifying device for a fuel cell according to claim 1, wherein: The longitudinal axis of the upper tube coincides with the longitudinal axis of the lower tube, the inner diameter of the upper tube is larger than the inner diameter of the lower tube; the ratio of the inner diameter of the guide tube to the inner diameter of the lower tube is 0.5-0.

6.

4. The humidifying device for a fuel cell according to claim 1, wherein: A demister is further provided in the upper cylinder. The demister is located above the gas-liquid separation chamber, and the wet gas outlet is provided above the demister. The demister is used to filter liquid water in the humidified gas, and the demister is a wire mesh structure.

5. The humidifying device for a fuel cell according to claim 1, wherein: A gas distributor is provided in the lower tube. The gas distributor is located below the guide tube and is arranged horizontally. The gas distributor is used to evenly disperse the gas in the humidified water. The gas distributor is connected to the dry gas inlet. A plurality of second through holes are provided on the gas distributor to connect the dry gas inlet and the central liquid rising chamber.

6. The humidifying device for a fuel cell according to claim 1, wherein: The dry gas pipeline is provided with a flow controller, which is used to adjust the flow of dry gas; the dry gas pipeline is also provided with at least one air pressure sensor; The air outlet pipeline is provided with at least one air pressure sensor, at least one air temperature sensor and at least one relative humidity sensor; the air outlet pipeline is also provided with a back pressure regulating valve, which is used to control the front end pressure of the fuel cell stack; the air outlet pipeline is also provided with a heating and insulation component, which is used to control the humidified gas to a preset temperature.

7. The humidifying device for a fuel cell according to claim 1, wherein: The gas management unit also includes a nitrogen purge pipeline, which is used to replace the atmosphere of the humidifier and the dry gas pipeline during the startup and shutdown of the humidifier; the gas management unit also includes an exhaust gas discharge pipeline.

8. The humidifying device for a fuel cell according to claim 7, characterized in that: The nitrogen purge pipeline is provided with an on-off valve and a nitrogen regulating valve, wherein the on-off valve is used to control the on-off of nitrogen, and the nitrogen regulating valve is used to control the flow and pressure of nitrogen.

9. The humidifying device for a fuel cell according to claim 1, wherein: The humidifying device further includes an electronic control unit, which is used for power supply, calculation and sending instructions. The electronic control unit is electrically connected to the gas management unit, the humidifier, the temperature control unit and the water supply and drainage unit.

10. The humidifying device for a fuel cell according to claim 1, wherein: The temperature control unit includes a circulating water pump, a heater and a cooler that are connected in sequence. The circulating water pump is used to transport the humidifying water in the humidifier to a circulation loop; the temperature control unit includes at least two water temperature sensors.

11. A parameter control method for a humidifying device of a fuel cell, characterized in that: The heating device is a humidifying device for a fuel cell according to any one of claims 1 to 10, and the parameter control method comprises: S1. Obtain the real-time flow rate of dry gas. When the real-time flow rate of dry gas is greater than or equal to the preset flow rate of dry gas, jump to step S2. S2, determining whether the difference between the real-time relative humidity value of the fuel cell humidification device and the relative humidity target value is within a preset relative humidity difference threshold range; if so, jump to step S3; if not, jump to step S4; S3, determining whether the difference between the real-time temperature value and the target temperature value of the fuel cell humidification device is within a preset temperature difference threshold range; if so, jump to step S5; if not, jump to step S6; S4, executing a preset relative humidity control method; S5, determining whether the difference between the real-time air pressure value of the fuel cell humidification device and the air pressure target value is within a preset air pressure difference threshold range; if so, maintaining the state until the program ends; if not, jumping to step S7; S6, the heating power of the heating belt of the humidifying device is adjusted in real time; S7. The back pressure regulating valve of the humidifying device adjusts the opening duty cycle.

12. The parameter control method of a fuel cell humidification device according to claim 11, characterized in that: The method for executing a preset relative humidity control comprises: The temperature controller of the humidifying device cooperatively controls the heating power of the heater and the cooling power of the cooler.

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