Cathode humidity regulation and control system and method for anode independent liquid supply AEM electrolytic bath

Abstract

The invention discloses a system and a method for regulating and controlling the humidity of a cathode of an anode independent liquid supply AEM electrolytic bath. The system and the method are used for solving the problem of drying of a cathode film surface under high current density. The system comprises an electrolytic bath main body, a gas-liquid separation module and a humidification module. And an interface humidity adjusting layer is arranged in a cathode membrane electrode assembly of the electrolytic bath main body. Wet hydrogen produced by the cathode enters the gas-liquid separation module through the outlet to separate liquid water, and the liquid water is conveyed to the humidification module at the inlet end of the cathode and is converted into water vapor or fog drops to be mixed with hydrogen produced by the cathode to form humidified hydrogen backflow. Moisture in the humidified hydrogen is adsorbed by the interface humidifying layer and is uniformly diffused to a cathode film-electrode interface in the in-plane direction of the interface humidifying layer so as to maintain interface wetting. According to the method, independent moisture closed-loop circulation on the cathode side is constructed, so that self-regulation of the humidity of the cathode under the condition that external liquid supply is not needed is realized, the problems of moisture loss and non-uniform distribution caused by electroosmosis dragging are solved, and the operation stability and durability of the AEM electrolytic cell under high current density are remarkably improved.

Description

A cathode humidity control system and method for an AEM electrolyzer with separate anode supply. Technical Field

[0001] This invention relates to the field of hydrogen production by water electrolysis, specifically to a cathode humidity control system and method for an AEM electrolyzer with separate anode liquid supply. Background Technology

[0002] With the global energy structure undergoing a low-carbon transformation, water electrolysis for hydrogen production has attracted widespread attention as a key pathway to achieve large-scale renewable energy storage and green chemical production. Among them, anion exchange membrane water electrolysis (AEMWE) technology, with its ability to operate in low-concentration alkaline environments, use of non-precious metal catalysts, and compact system structure, is considered a next-generation hydrogen production technology that combines the advantages of alkaline electrolysis and proton exchange membrane (PEM) electrolysis.

[0003] As AEM (Alternating Electrolysis) water electrolysis technology advances towards higher current densities and commercialization, cathode drying has become the most prominent operational bottleneck in typical anode-only liquid supply modes. The fundamental reason lies in the OH- content in the AEM electrolyzer. - The migration direction of the electrolyte is the same as that of water. Water is continuously carried from the cathode to the anode by electroosmosis, causing the cathode to lose a stable source of water. This is quite different from proton exchange membrane (PEM) electrolyzers, where H2O is... + During migration towards the cathode, moisture is carried back, thus preventing cathode drying. In the AEM system, as the current density increases, water transfer caused by electroosmotic drag becomes dominant, leading to a continuous decrease in the water content of the cathode membrane surface. Furthermore, water consumption from the cathode hydrogen production reaction itself, water evaporation from the produced hydrogen gas, and water evaporation caused by localized temperature rise further accelerate water loss at the cathode interface. When the cathode region lacks a timely water replenishment mechanism, the membrane-electrode interface exhibits decreased water content, increased resistance, and shrinkage of the active region of the catalyst layer. This results in localized overheating, increased risk of gas cross-permeation, and wet-dry cycle fatigue of the membrane material, severely impacting stack durability and overall efficiency.

[0004] Current humidity control strategies mainly include direct cathode liquid supply and membrane electrode structure modification. The former requires an independent liquid circuit and increases the difficulty of gas-liquid separation; the latter relies on material properties to improve its own moisturizing ability, but the humidity control range is limited and long-term stability is difficult to guarantee. Therefore, how to achieve stable cathode humidification under high current density conditions without introducing an independent cathode liquid supply circuit is an urgent problem to be solved for the engineering application of AEM electrolyzers. Summary of the Invention

[0005] In response to the problem that in the existing technology of AEM electrolysis water system with separate anode supply, the cathode drying under high current density conditions can lead to a decrease in water content, an increase in resistance, and a decline in durability at the membrane-electrode interface, the present invention provides a cathode humidity control system and method for AEM electrolysis cell with separate anode supply. This system can maintain stable cathode humidity through self-regulation without the need for an independent cathode supply circuit.

[0006] This invention is achieved through the following technical solution: Firstly, this application provides a cathode humidity control system for an AEM electrolyzer with a separately supplied anode, comprising: an electrolyzer body having a cathode inlet and a cathode outlet, wherein an interface humidity control layer is disposed in the cathode membrane electrode assembly of the electrolyzer body; a gas-liquid separation module, the inlet of which is connected to the cathode outlet, for separating liquid water from the cathode-generated hydrogen gas; and a humidification module, the liquid inlet of which is connected to the liquid outlet of the gas-liquid separation module, wherein a humidification section is disposed corresponding to the cathode inlet, for converting the liquid water from the gas-liquid separation module into gaseous water, and mixing it with the cathode-generated hydrogen gas entering from the cathode inlet to form humidified hydrogen gas; wherein, after the humidified hydrogen gas enters the electrolyzer body, the moisture contained therein is adsorbed by the interface humidity control layer and diffused to the cathode membrane-electrode interface adjacent to the interface humidity control layer, thereby maintaining the wetting state of the interface.

[0007] Preferably, the interface humidity conditioning layer is disposed within the cathode membrane electrode assembly and is located between the cathode catalytic layer and the gas diffusion layer.

[0008] Preferably, the interface humidity conditioning layer includes one or a combination of the following structural features: (1) the interface humidity conditioning layer has a microporous network structure with three-dimensional through pores; (2) the interface humidity conditioning layer has a wettability gradient structure, with the wettability in the region near the cathode inlet end being higher than that in the region far from the cathode inlet end; (3) the interface humidity conditioning layer is a composite moisture-wicking thin layer structure with hydrophilic materials on its surface or inside; (4) the interface humidity conditioning layer has a capillary channel structure inside for guiding the directional diffusion of moisture.

[0009] Preferably, it also includes a water return passage, which connects the liquid outlet of the gas-liquid separation module and the liquid inlet of the humidification module.

[0010] Preferably, the liquid inlet of the humidification module and / or the outlet of the return water passage are located at the lowest potential energy position of the system.

[0011] Preferably, it also includes a pressure stabilization module, which is located downstream of the gas outlet of the gas-liquid separation module.

[0012] Preferably, the humidification module includes at least one of a microporous hydrophilic membrane, a capillary core, or a micro-spray device.

[0013] Preferably, the gas-liquid separation module is a condenser separator, a cyclone separator, an inertial collision separator, or a membrane separation component.

[0014] Preferably, it further includes a humidity detection and control module; the humidity detection and control module includes a first humidity sensor disposed at the cathode inlet end, a second humidity sensor disposed at the cathode outlet end, and a controller that is signal-connected to the first humidity sensor, the second humidity sensor and the humidification module respectively.

[0015] Secondly, this application provides a method for controlling the cathode humidity of an AEM electrolyzer with a separately supplied anode, comprising the following steps: performing an electrochemical reaction on the cathode side of the electrolyzer to generate self-produced hydrogen; drawing out a mixed gas containing the self-produced hydrogen and its entrained moisture from the cathode outlet; performing gas-liquid separation on the mixed gas to obtain separated hydrogen and liquid water; converting the liquid water into gaseous water and mixing it with the self-produced hydrogen entering from the cathode inlet to form humidified hydrogen; and introducing the humidified hydrogen into the main body of the electrolyzer, so that the moisture contained therein is adsorbed by the interface humidity-regulating layer disposed in the cathode membrane electrode assembly and diffused to the cathode membrane-electrode interface to maintain the wetting state of the interface.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The cathode humidity control system of the AEM electrolyzer with a separate anode liquid supply provided in this application addresses the inherent problem of cathode dehydration due to electroosmotic drag during high current density operation of the AEM electrolyzer with a separate anode liquid supply. It constructs a closed-loop internal moisture circulation system on the cathode side, completely independent of the anode liquid path. First, the moisture carried in the wet hydrogen gas of the reaction product is captured and condensed into liquid water by the gas-liquid separation module located at the cathode outlet. Second, this liquid water is transported to the cathode inlet through the return water passage. Finally, the humidification module converts it back into gaseous water, which mixes with the newly generated self-produced hydrogen gas at the cathode to form a humidity-controlled wet hydrogen gas reflux. Furthermore, by introducing an interface humidity-regulating layer, which is placed inside the cathode membrane electrode assembly, its function is not passive water storage, but rather active secondary distribution of the refluxed moisture: through its porous or gradient structure, it rapidly and uniformly diffuses the relatively concentrated moisture at the inlet to the entire cathode catalyst layer and ion exchange membrane contact interface in a direction parallel to the membrane surface. With a minimalist architecture that does not require any external cathode liquid supply lines, active and dynamic compensation for lost moisture is achieved. This fundamentally solves the problem of uneven distribution of inlet over-wetness and outlet dryness that is easily caused by traditional water replenishment methods, ensuring the uniformity and stability of the wetting state of the entire reaction interface. This effectively reduces the interface resistance and improves the operating efficiency and stack durability under high current density. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 is a schematic diagram of the overall structure of the cathode humidity control system of the present invention; Figure 2 is a schematic diagram of the structural arrangement of the interface humidity control layer in the membrane electrode assembly of the present invention.

[0019] In the diagram: 1-Electrolytic cell body; 2-Cathode inlet; 3-Inlet humidification module; 4-Cathode outlet; 5-Gas-liquid separation module; 6-Return water passage; 7-Pressure stabilization module; 8-Interface humidity conditioning layer; 9-Cathode catalytic layer; 10-Gas diffusion layer.

[0020] In the diagram, solid arrows indicate the flow path of hydrogen produced at the cathode, while dashed arrows indicate the flow path of recycled water. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] The electrolyzer described in this invention is the core electrochemical unit of an anion exchange membrane water electrolysis hydrogen production system. It employs a typical sandwich structure, sequentially comprising an anode flow field plate, an anode catalyst layer, an anion exchange membrane, a cathode catalyst layer, and a cathode flow field plate. Alkaline electrolyte is introduced to the anode side for the oxygen evolution reaction, while the cathode side receives no external electrolyte supply and relies solely on water diffused from the anode for the hydrogen evolution reaction. Under high current density operation, water on the cathode side continuously migrates towards the anode due to electroosmotic drag, leading to a decrease in water content and an increase in resistance at the membrane-electrode interface, affecting system efficiency and durability. This invention, without altering the internal structure of the electrolyzer, constructs a closed-loop humidity control system outside the cathode gas path, incorporating gas-liquid separation, water return, and humidification. This system actively replenishes and stably maintains water at the cathode interface, thereby improving overall performance.

[0028] A cathode humidity control system for an AEM electrolyzer with separate anode liquid supply includes an electrolyzer body 1, a gas-liquid separation module 5, and a humidification module 3. The electrolyzer body 1 has a cathode inlet end 2 and a cathode outlet end 4. The cathode outlet end 4 is connected to the inlet of the gas-liquid separation module 5, and water-containing hydrogen gas is introduced into the gas-liquid separation module 5. The gas outlet of the gas-liquid separation module 5 is used to output the separated dry hydrogen gas, and its liquid outlet is connected to the humidification module 3. The humidification module 3 is located at the cathode inlet end 2 and is used to receive liquid water from the gas-liquid separation module 5 and convert it into gaseous water, which is then introduced into the hydrogen gas flow generated when the cathode of the electrolyzer body enters from the cathode inlet end 2.

[0029] It should be noted that the cathode inlet 2 of the electrolytic cell body 1 serves as the starting point for the self-generated hydrogen at the cathode of the electrolytic cell body 1. This hydrogen is generated inside the electrolytic cell body 1 through a cathode electrochemical reaction, rather than being introduced from the outside. The generated hydrogen flows unidirectionally from the cathode outlet 4 along the internal flow channel.

[0030] This cathode humidity control system, designed for AEM electrolyzers with separate anode liquid supply, effectively solves the core problem of cathode film drying under high current density by constructing an internal water circulation system on the cathode side. The principle involves separating and recovering moisture carried in hydrogen at the cathode gas outlet and transporting the recovered water to the cathode inlet, where it is reintroduced into the newly generated hydrogen through a humidification device. This utilizes the flow of hydrogen itself to achieve a closed-loop circulation of moisture on the cathode side, continuously replenishing the interfacial moisture lost due to electroosmosis. The advantages of this system are that it completely avoids a complex independent cathode liquid supply system, significantly reducing system complexity and energy consumption while maintaining the purity of the anolyte path, and improving operational reliability and durability.

[0031] In some embodiments, the gas-liquid separation module 5 is connected to the inlet of the humidification module 3 via the return water passage 6, and the outlet of the humidification module 3 is connected to the cathode inlet 2 of the electrolytic cell body.

[0032] The liquid water separated by the gas-liquid separation module 5 enters the humidification module through the return water passage 6. The humidification module converts the liquid water into gaseous water molecules, and then introduces the gaseous water molecules into the self-generated hydrogen gas to obtain suitable humidity before entering the flow channel. The humidified hydrogen gas enters the gas-liquid separation module 5 through the cathode outlet 4. The gas-liquid separation module 5 is used to separate water from the hydrogen gas produced by the cathode, separate and collect the water vapor and droplets entrained in the hydrogen gas as liquid water, and transport it to the inlet humidification module 3 through the return water passage to participate in the humidity control process again.

[0033] It should be noted that the gas-liquid separation module only acts on the cathode-side gas and is completely isolated from the anolyte circuit, so it does not affect the anolyte supply or the concentration of the alkali solution.

[0034] The gas-liquid separation module 5 uses a cooling and condensation method to achieve water separation. Its structure may include a condenser plate, a liquid collection chamber, and a gas-liquid separation channel. Of course, the specific structural form of the gas-liquid separation module is not limited, and it can also be a cyclone separator, an inertial collision separator, a membrane separation component, or other devices that can effectively separate hydrogen and water.

[0035] The humidification module 3 is a device for converting liquid water into water vapor or droplets and introducing it into the cathode hydrogen gas flow, including at least one of a microporous hydrophilic membrane, a capillary core, or a micro-spray device.

[0036] Preferably, the return water passage 6 is used to transport the liquid water in the gas-liquid separation module 5 to the inlet humidification module 3. The humidification module 3 is set at the lowest potential energy position so that the liquid water in the return water passage can smoothly enter the inlet humidification module under gravity.

[0037] In some embodiments, the gas outlet of the gas-liquid separation module 5 is connected to the pressure stabilization module 7. The pressure stabilization module is used to regulate the pressure of the output hydrogen. By using appropriate back pressure, the stability of gas-liquid co-flow can be improved, the ability of moisture to be carried into the flow channel by hydrogen can be enhanced, and the wetting effect of the interface moisture conditioning layer can be strengthened.

[0038] The pressure stabilization module 7 is a back pressure valve, pressure regulating valve, or other device with pressure stabilization function.

[0039] In another embodiment, to further improve the water content stability of the cathode-side membrane-electrode interface, an interface humidity regulating layer 8 is provided in the cathode membrane electrode assembly of the electrolytic cell body. This layer is used to adsorb, maintain, and regulate the diffusion of moisture at the membrane interface in the in-plane direction without changing the closed-loop humidity path configuration of the system.

[0040] The electrolytic cell body 1 contains its core membrane electrode assembly, which is composed of an anode catalyst layer, an anion exchange membrane, and a cathode membrane electrode assembly in sequence. The cathode membrane electrode assembly is located on the side of the anion exchange membrane facing the cathode chamber and is a multi-layer composite structure formed by the cathode catalyst layer, the gas diffusion layer, and the anion exchange membrane on the cathode side.

[0041] The interface humidity conditioning layer 8 is disposed between the cathode catalytic layer 9 and the gas diffusion layer 10.

[0042] In another embodiment, the interface moisture-regulating layer typically has through-holes or a pore network to ensure that it has a certain moisture adsorption capacity and lateral diffusion channels. Through capillary force, wettability difference, or surface energy gradient, the interface moisture-regulating layer can adsorb local moisture carried at the inlet end and diffuse it inward within the layer, thereby forming a continuous and uniform wetted interface.

[0043] The interface moisture-regulating layer includes at least one structure selected from microporous network structure, wettability gradient structure, composite moisture-wicking thin layer structure and moisture-wicking channel structure, or a combination of multiple structures.

[0044] (1) The interface humidity control layer has a three-dimensional interconnected microporous network structure with a pore size of 1-50 μm and a porosity of 30%-80%, which is used to adsorb and promote the rapid diffusion of water within the layer; (2) The interface humidity control layer has a wettability gradient structure, which exhibits stronger hydrophilicity in the region near the cathode channel inlet and gradually weakens wettability along the flow direction to the outlet, thereby driving water to spread evenly from the inlet side to the outer periphery of the membrane surface; (3) The interface humidity control layer is a composite moisture-conducting thin layer structure, which has at least one of hydrophilic nanoparticles, metal oxide layers or organic hydrophilic coatings on its surface or inside, which is used to enhance the adsorption capacity of water and the stability of the liquid film; (4) The interface humidity control layer has a moisture-conducting channel structure, which has regularly arranged or gradually changing capillary channels inside, which is used to guide water to diffuse in a direction parallel to the membrane surface.

[0045] The interface humidity regulating layer 8 has a thin layer structure, including but not limited to porous materials, hydrophilic fiber membranes, or composite thin layers with hydrophilic surfaces.

[0046] It should be noted that the interfacial humidity-regulating layer does not participate in the electrochemical reaction; its function is to improve the interfacial moisture state. Its material composition, pore structure, or wetting properties can be adjusted according to the specific application environment and cost conditions. Any film structure that can achieve moisture adsorption, retention, and in-plane diffusion can be used for interfacial humidity regulation in this technical solution.

[0047] In some embodiments, the humidification module, the outlet gas-liquid separation module, and the pressure stabilization module are connected to the control module to control the operating status of each module.

[0048] Furthermore, the system also includes a humidity monitoring module, which is a humidity sensor installed at both the cathode inlet and cathode outlet, and connected to the control module.

[0049] The humidity sensor at the cathode inlet directly monitors the water replenishment intensity, serving as a direct feedback signal for controlling the humidification module (such as adjusting the atomization amount and evaporation power) to ensure the inlet humidity setpoint.

[0050] A humidity sensor at the cathode outlet monitors the humidity of the wet hydrogen gas flowing out of the electrolyzer, reflecting the overall moisture carryover within the flow channel and the moisture balance at the reaction interface. Too low an outlet humidity indicates potential water shortage at the interface; too high a humidity may indicate a risk of liquid accumulation in the flow channel. This signal can be used to coordinate the adjustment of inlet humidification and pressure stabilization.

[0051] Correspondingly, this application also provides a method for controlling the cathode humidity of an AEM electrolyzer with a separate anode supply, comprising the following steps: performing an electrochemical reaction on the cathode side of the electrolyzer to generate self-produced hydrogen; drawing out a mixed gas containing the self-produced hydrogen and its entrained moisture from the cathode outlet; performing gas-liquid separation on the mixed gas to obtain separated hydrogen and liquid water; converting the liquid water into gaseous water and mixing it with the self-produced hydrogen entering from the cathode inlet to form humidified hydrogen; and introducing the humidified hydrogen into the main body of the electrolyzer, so that the moisture contained therein is adsorbed by the interface humidity-regulating layer disposed in the cathode membrane electrode assembly and diffused to the cathode membrane-electrode interface to maintain the wettability of the interface.

[0052] The interface moisture-regulating layer has a wettability gradient structure, with higher wettability in the region near the cathode inlet than in the region far from the cathode inlet; the method further includes: driving moisture to diffuse directionally from the cathode inlet to the peripheral region of the cathode film-electrode interface through the wettability gradient structure.

[0053] Furthermore, the gas humidity at the cathode inlet and / or cathode outlet is detected, and the conversion rate or conversion method of the liquid water is adjusted according to the detected humidity.

[0054] For example, adjusting the discharge pressure of the cathode-side gas can help control the carrying and distribution of moisture in the humidified hydrogen gas.

[0055] Example 1 Referring to Figures 1 and 2, a cathode humidity control system for an AEM electrolyzer with separate anode liquid supply includes an electrolyzer body 1, a gas-liquid separation module 5, and a humidification module 3.

[0056] The electrolyzer body 1 has a cathode inlet 2 and a cathode outlet 4. The cathode outlet 4 is connected to the inlet of the gas-liquid separation module 5, and is used to introduce the hydrogen produced at the cathode and its entrained moisture into the gas-liquid separation module 5. The gas outlet of the gas-liquid separation module 5 is used to output the separated hydrogen, and its liquid outlet is connected to the humidification module 3 through the return water passage 6. The humidification module 3 is located at the cathode inlet 2, and is used to receive liquid water from the gas-liquid separation module 5, and convert it into gaseous water or atomized water droplets, which are then introduced into the self-produced hydrogen entering the electrolyzer body from the cathode inlet 2.

[0057] Furthermore, to improve the lateral diffusion uniformity and stability of moisture at the cathode membrane electrode interface, an interface humidity-regulating layer 8 is provided in the cathode membrane electrode assembly of the electrolytic cell body 1. This interface humidity-regulating layer 8 is disposed between the cathode catalyst layer 9 and the gas diffusion layer 10, and employs a microporous network structure with three-dimensional interconnected pores. Its pore size is 1-50 μm, and its porosity is 30%-80%. This structure can effectively adsorb moisture carried on the inlet side and rapidly diffuse it towards the membrane surface within the layer through capillary action, forming a continuously humid interface environment, thereby inhibiting the formation of localized dry spots.

[0058] During system operation, the wet hydrogen gas generated at the cathode enters the gas-liquid separation module 5 through outlet 4. The moisture is condensed and separated into liquid water, and the dried hydrogen gas is output from the system. The liquid water is transported to the humidification module 3 by gravity through the return water passage 6, where it evaporates or atomizes and is reintroduced into the newly generated hydrogen gas. The humidified hydrogen gas enters the cathode flow channel. When it flows through the interface humidification layer 8, the moisture is adsorbed by the humidification layer and spread evenly along the membrane surface, continuously replenishing the moisture lost at the interface between the cathode catalyst layer and the ion exchange membrane due to electroosmosis.

[0059] Through the synergistic effect of gas-liquid separation, return water humidification, and interface humidity conditioning, this embodiment achieves closed-loop circulation of cathode-side moisture and autonomous stable control of interface humidity without the need to add an independent cathode liquid path, significantly improving the operational stability and durability of the AEM electrolyzer under high current density.

[0060] This application discloses a cathode humidity control system for an AEM electrolyzer with a separately supplied anode. Compared with existing technologies, it has the following advantages: 1. Independent moisture circulation on the cathode side avoids cross-contamination of the system. The gas-liquid separation module is located in the cathode hydrogen production branch, and the recovered moisture circulates only within the cathode path and does not enter the anode liquid path, thereby avoiding problems such as alkali concentration fluctuations, ion cross-migration, and electrode interface contamination. This structure ensures the independence and stability of cathode moisture management at the system level.

[0061] 2. Moisture migrates along the main flow direction, resulting in a balanced humidity distribution and no risk of backflow. The return water inlet is located at the inlet end of the cathode channel or at the lowest potential energy position, allowing the recovered water to gradually migrate along the channel axis under the combined action of airflow and gravitational potential energy. The humidity exhibits a natural and balanced distribution from the inlet to the outlet, significantly reducing the possibility of local liquid accumulation, air resistance, and reverse liquid flow.

[0062] 3. The interface humidity conditioning layer facilitates the conversion of incoming moisture into a continuous thin film, improving the uniformity of film surface wetting. The humidity conditioning layer, sandwiched between the cathode catalytic layer and the gas diffusion layer, has a porous structure or wettability gradient, which promotes the diffusion and spread of inlet-end moisture within the layer into a continuous liquid film, forming a stable in-plane wetting region. This structure significantly reduces the probability of localized dry areas at the membrane electrode interface, ensuring interfacial conduction stability at the material scale.

[0063] 4. Construct a closed-loop cathode humidity control system to improve stability without increasing the need for an independent liquid supply. The combination of water recovery, inlet return water, interfacial diffusion, and pressure stabilization structures forms a complete cathode humidity control path, enabling the circulation and dynamic adjustment of moisture within the cathode. The system achieves high humidity stability and membrane wetting without requiring an independent cathode liquid supply loop, reducing structural complexity, auxiliary energy consumption, and long-term operation and maintenance costs.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A cathode humidity control system for an AEM electrolytic cell with separate anode supply, characterized in that, include: An electrolytic cell body has a cathode inlet end and a cathode outlet end, and an interface humidity conditioning layer is provided in the cathode membrane electrode assembly of the electrolytic cell body. A gas-liquid separation module, the inlet of which is connected to the cathode outlet, is used to separate liquid water from the hydrogen-generated gas at the cathode. The humidification module has a liquid inlet connected to the liquid outlet of the gas-liquid separation module, and its humidification section is set corresponding to the cathode inlet end. It is used to convert liquid water from the gas-liquid separation module into gas water and mix it with cathode-generated hydrogen entering from the cathode inlet end to form humidified hydrogen. The humidified hydrogen enters the main body of the electrolyzer, and the water contained in it is adsorbed by the interface humidity control layer and diffused to the cathode film-electrode interface adjacent to the interface humidity control layer to maintain the wettability of the interface.

2. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, The interface humidity conditioning layer is disposed within the cathode membrane electrode assembly and is located between the cathode catalytic layer and the gas diffusion layer.

3. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, The interface humidity control layer includes one or a combination of the following structural features: (1) the interface humidity control layer has a microporous network structure with three-dimensional through pores; (2) the interface humidity control layer has a wettability gradient structure, with the wettability in the region near the cathode inlet being higher than that in the region far from the cathode inlet; (3) the interface humidity control layer is a composite moisture-wicking thin layer structure with hydrophilic materials on its surface or inside; (4) the interface humidity control layer has a capillary channel structure inside for guiding the directional diffusion of moisture.

4. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, It also includes a water return path, which connects the liquid outlet of the gas-liquid separation module to the liquid inlet of the humidification module.

5. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, The liquid inlet of the humidification module and / or the outlet of the return water passage are located at the lowest potential energy position of the system.

6. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, It also includes a pressure stabilization module, which is located downstream of the gas outlet of the gas-liquid separation module.

7. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, The humidification module includes at least one of a microporous hydrophilic membrane, a capillary core, or a micro-spray device.

8. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, The gas-liquid separation module is a condenser separator, a cyclone separator, an inertial collision separator, or a membrane separation component.

9. The cathode humidity control system for an AEM electrolytic cell with separate anode supply according to claim 1, characterized in that, It also includes a humidity detection and control module; the humidity detection and control module includes a first humidity sensor disposed at the cathode inlet end, a second humidity sensor disposed at the cathode outlet end, and a controller that is respectively connected to the first humidity sensor, the second humidity sensor and the humidification module.

10. A method for controlling the cathode humidity of an AEM electrolytic cell with separate anode supply as described in any one of claims 1-9, characterized in that, The process includes the following steps: an electrochemical reaction is carried out on the cathode side of the electrolyzer to generate self-produced hydrogen; a mixed gas containing the self-produced hydrogen and its entrained moisture is drawn out from the cathode outlet; the mixed gas is subjected to gas-liquid separation to obtain separated hydrogen and liquid water; the liquid water is converted into gaseous water and mixed with the self-produced hydrogen entering from the cathode inlet to form humidified hydrogen; the humidified hydrogen is introduced into the main body of the electrolyzer, so that the moisture contained therein is adsorbed by the interface humidity-regulating layer disposed in the cathode membrane electrode assembly and diffused to the cathode membrane-electrode interface to maintain the wetting state of the interface.

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