PEM electrolytic bath integral base plate assembly and PEM electrolytic bath thereof

Abstract

The invention relates to the technical field of water electrolysis hydrogen production, and particularly provides a PEM electrolytic bath integral base plate assembly and a PEM electrolytic bath thereof. The integral type base plate assembly comprises an integral type base plate of a step-shaped structure, a groove is formed in a thickness thinning area of the integral type base plate, a buffer stretching strip is embedded in the groove, and a plurality of positioning pieces are arranged on the periphery of the integral type base plate assembly and used for circumferentially limiting a membrane electrode assembly (MEA); an anode runner and a cathode runner are respectively processed on the front and back surfaces of a single material, the functions of anode and cathode plates are integrated, and a traditional bipolar plate discrete structure is abandoned. According to the PEM electrolytic cell based on the assembly, cathode and anode runners are integrated on the same base plate, sealing rubber strips between independent polar plates are omitted, the sealing performance is enhanced, and hydrogen and oxygen leakage is avoided; parts such as sealing rubber strips and independent polar plates are reduced, and the material and assembly cost is reduced; meanwhile, the assembly process is simplified, the assembly time is shortened by more than 20%, the mounting efficiency of the electrolytic cell is improved, and technical support is provided for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of water electrolysis for hydrogen production, and particularly to an integral pad assembly for a PEM electrolyzer and the PEM electrolyzer thereof. Background Technology

[0002] Currently, large-scale hydrogen production projects generally use large-scale PEM (Proton Exchange Membrane) electrolyzers as the core hydrogen production unit. After purification and filtration pretreatment, the produced hydrogen needs to be transported to a hydrogen storage tank for storage or transportation via a pressurization system. This pressurization system typically employs a two-stage pressurization process to achieve stable hydrogen pressure increase. To ensure the reliable operation of the two-stage pressurization process, it is necessary to maintain a specific initial pressure at the hydrogen outlet of the electrolyzer cathode. According to current industry standards, the hydrogen-side operating pressure is generally set in the range of 1.6-3.0 MPa, and flexible adjustment within this range is supported. Therefore, mainstream large-scale PEM electrolyzers must integrate hydrogen-side back pressure regulation functions.

[0003] The design requirements of this back pressure regulation function directly increase the precision requirements of the internal structure of the electrolyzer: in particular, the inner frame of the anode and cathode gaskets and the gas diffusion layer (GDL) need to achieve an extremely high precision tight fit. Specifically, the assembly gap between the gas diffusion layer and the gaskets must be strictly controlled within 0.1 mm. If the gap exceeds this limit, under the long-term effect of the anode-cathode pressure difference, the risk of uneven stress or local stress concentration in the MEA (Membrane Electrode Assembly) increases significantly, thereby accelerating its failure probability. To meet the above-mentioned micron-level (≤0.1 mm) assembly precision requirements, high-precision machining of key components (such as gaskets, sintered titanium plates, etc.) is required, and the tolerance fit of each component must be strictly controlled during the assembly process.

[0004] Currently, mainstream PEM electrolyzers generally adopt a combined design of independent gaskets for the anode and cathode. However, during the entire life cycle of the equipment, especially under harsh conditions such as high temperature, high pressure, and strong corrosion, the long-term sealing reliability of this independent gasket structure faces significant challenges. It is prone to problems such as sealing failure and increased gaps, which affect the stable operation and service life of the electrolyzer. Summary of the Invention

[0005] This invention addresses the shortcomings of existing membrane electrode assemblies (MEAs) that are sandwiched between anode and cathode gaskets and rely on double-sided sealing strips for gas path isolation, resulting in issues such as easy leakage and complex assembly. It innovatively uses a single piece of material with anode and cathode channels machined on both sides, achieving integrated anode and cathode functions and eliminating the traditional separate bipolar plate structure. A stepped, integral gasket is used, with grooves and embedded buffer stretch strips in its thinned area, and several positioning elements around it. The anode-side buffer stretch strip effectively blocks gas leakage paths, while the MEA, pressed against the buffer stretch strip, increases friction to prevent deformation. Furthermore, the peripheral positioning elements precisely constrain the relative position of the MEA and the anode diffusion layer, suppressing component displacement during operation. This design not only fundamentally improves the reliability of gas path sealing but also simplifies the assembly process, reducing assembly time by more than 20% and significantly improving installation efficiency. The technical solution provided by this invention is as follows: On one hand, the present invention provides an integral pad assembly for a PEM electrolytic cell, comprising: An integral pad with a stepped structure, wherein a groove is formed in the thickness reduction area of ​​the integral pad, and a buffer tension strip is embedded in the groove; The periphery of the thickness reduction zone is provided with several positioning elements for circumferentially limiting the membrane electrode assembly.

[0006] In some specific embodiments, the thickness reduction zone has a longitudinal length of 0.1-50 mm along the elongated structure in which it is located; the groove has a depth of 0.1-2 mm, a width of 0.1-10 mm, and the center line of the groove is 1-15 mm away from the inner edge of the integral pad.

[0007] In some specific embodiments, the compression rate of the buffer stretch strip is 5-50%, and the filling amount is 50-90%.

[0008] In some specific embodiments, the integral pad is made of one or more of the following raw materials: polyetherimide, polysulfone, polytetrafluoroethylene, polyoxymethylene, and polyamide, wherein the raw materials include pure materials and modified materials; at least a portion of the thickness reduction area is made of one or more of the following raw materials: rubber, polyurethane, resin, and silicone, wherein the raw materials include pure materials and modified materials.

[0009] In some specific embodiments, protrusions are provided in the thickness reduction area to replace the grooves.

[0010] On the other hand, the present invention also provides a PEM electrolytic cell, including the above-described integral pad assembly, and an anode titanium mesh, an anode diffusion layer, a membrane electrode assembly, a cathode diffusion layer and a cathode titanium mesh sequentially stacked on the integral pad assembly along the anode to cathode direction; the anode diffusion layer and the cathode diffusion layer are porous sintered titanium layers.

[0011] In some specific embodiments, a mounting gap of 0.1-1 mm is formed between the outer periphery of the anode titanium mesh, the anode diffusion layer and the membrane electrode assembly and the thickness reduction area of ​​the integral pad.

[0012] In some specific embodiments, when the integral pad assembly is stacked with the anode titanium mesh, anode diffusion layer, membrane electrode assembly, cathode diffusion layer and cathode titanium mesh, the applied pressing pressure is 0-3 MPa.

[0013] In some specific embodiments, the porous sintered titanium layer has a porosity of 10-50%, a thickness of 0.5-2 mm, and a density of 3.0-4.0 g / cm³. 3 Furthermore, the deformation of the porous sintered titanium layer is 1-20%. In some specific embodiments, the titanium mesh wire diameter of the anode titanium mesh and the cathode titanium mesh is 0.3-1.2 mm, the thickness is 0.5-2 mm, and the density is 1.5-2.0 g / cm³. 3 And the deformation after molding is 5-10%.

[0014] In some specific embodiments, the outer periphery of the membrane electrode assembly is sealed on one side with polyethylene naphthalate (PEN) material, and the sealing width is 5-50 mm.

[0015] By adopting the above technical solution, the integrated pad assembly for a PEM electrolyzer and the PEM electrolyzer provided by the present invention have the following beneficial effects: 1. This invention innovatively integrates the functions of the anode and cathode plates into a single integral pad, with anode and cathode flow channels machined on both sides respectively, successfully eliminating the traditional separate bipolar plate structure. This design eliminates the need for sealing strips between two independent plates, fundamentally enhancing the sealing performance of the overall structure and effectively avoiding the risk of hydrogen and oxygen gas leakage caused by aging of the sealing strips or improper assembly. Simultaneously, it reduces the material consumption and quantity of sealing strips and independent plates, significantly lowering production and assembly costs. Furthermore, compared to the traditional separate plate structure, the new design simplifies the assembly process, shortening assembly time by more than 20%, improving installation efficiency, and providing strong technical support for the large-scale production and reliable operation of PEM electrolyzers.

[0016] 2. To optimize reliability under differential pressure operating conditions, the thickness reduction zone is designed to be 5-15mm along the longitudinal length of the long strip structure. This allows the inner frame size of the cathode to be precisely reduced by 5-15mm compared to the inner frame size of the anode, forming a reasonable frame size difference. This ensures that the membrane electrode assembly (MEA) can still be effectively protected while maintaining an assembly gap of ≤0.5mm between the gas diffusion layer and the inner frame of the gasket. This fundamentally avoids mechanical damage to the MEA caused by the differential pressure between the anode and cathode, thereby improving the stability of equipment operation and its overall service life.

[0017] 3. The integral pad adopts a stepped structure design, and grooves are opened in the thinning area. Buffer tension strips are embedded in the grooves. This structure can form a tight physical barrier between the hydrogen and oxygen chambers, effectively preventing cross-penetration of the two gases. This fundamentally eliminates the safety hazards that may be caused by gas cross-flow (such as the risk of explosion due to gas mixing). It not only improves the overall sealing reliability of the electrolytic cell, but also provides double protection for the safe and stable operation of the equipment under high pressure and high load conditions.

[0018] 4. Several positioning components are set around the thickness reduction zone. This structure can effectively improve the positional accuracy and assembly alignment of MEA, anode titanium mesh, and anode diffusion layer during the assembly process through the precise limiting effect of the positioning components, thereby improving assembly efficiency and significantly shortening assembly time. At the same time, the positioning components can form a stable mechanical constraint on MEA, anode titanium mesh, and anode diffusion layer, effectively suppressing relative displacement or offset caused by uneven force, temperature fluctuations, and other factors during equipment operation. This reduces the risk of MEA damage under extreme conditions such as friction, vibration, and pressure fluctuations, ensuring the structural stability and functional reliability of the electrolytic cell during long-term operation. 5. By innovatively optimizing the MEA edge banding structure, the traditional double-sided edge banding design has been improved into a single-sided edge banding structure. While ensuring that the overall strength of the edge banding fully meets the actual use requirements, the edge banding process is simplified, the process flow time in the production process is shortened, and the amount of edge banding material used is effectively reduced. This not only reduces the material and labor costs in the manufacturing process, but also improves production efficiency and economy.

[0019] 6. By adopting an optimized stepped integrated pad, the assembly tolerance of the anode titanium mesh, anode diffusion layer and MEA under single-sided high-pressure hydrogen production mode can be significantly relaxed from the conventional requirement of 0.1mm to 0.5mm (the accuracy requirement is reduced by 5 times). This effectively eliminates the risk of mechanical stress concentration in MEA caused by single-sided back pressure, which reduces the precision machining requirements of key components and improves the assembly efficiency of the electrolyzer. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the PEM electrolyzer provided in an embodiment of the present invention; Figure 2 This is an exploded view of the PEM electrolytic cell provided in an embodiment of the present invention.

[0022] The following is supplementary explanation of the attached figures: 1-Integral pad; 11-Thickness reduction zone; 12-Groove; 13-Positioning component; 2-Anode titanium mesh; 3-Anode diffusion layer; 4-Membrane electrode assembly; 5-Cathode diffusion layer; 6-Cathode titanium mesh. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. In the description of the invention, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for 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 of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0025] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0026] Please see Figure 1 and Figure 2 This invention provides an integral pad assembly for a PEM electrolytic cell, comprising: An integral pad 1 with a stepped structure has a groove 12 in its thickness reduction area 13, and a buffer stretching strip is embedded in the groove 12; a number of positioning elements 13 are provided around the thickness reduction area 13 for circumferentially limiting the membrane electrode assembly.

[0027] Specifically, this invention addresses the problems of long processing cycles and low efficiency caused by the traditional thin-plate (e.g., as thin as 2mm) design of anode and cathode gaskets. It innovatively proposes an integral gasket 1 with a stepped structure (i.e., a double-layer stepped gasket structure) based on the integrated processing of thick plates (e.g., as thick as 4mm). This integrated gasket 1 achieves the integrated support of the anode and cathode functional layers through the step height difference between the thickness reduction zone 13 (upper platform) and the lower base. The thickness reduction zone 13 supports the anode titanium mesh 2, the anode diffusion layer 3, and the membrane electrode assembly (MEA) 4, while the lower base supports the cathode diffusion layer 5 and the cathode titanium mesh 6. Compared to the traditional structure where the MEA is sandwiched between the anode and cathode gaskets and relies on double-sided sealing strips for gas path isolation, this solution assembles the MEA only in the thickness reduction zone 13 (anode... On the gasket side, a reliable sealing structure is formed by adding a buffer tension strip in the thickness reduction area 13. This completely blocks the gas leakage path to ensure gas circuit sealing, and increases the friction force through the pressing contact between the MEA and the buffer tension strip to prevent deformation. In addition, the integral gasket 1, through the MEA mounting recessed structure formed by the thickness reduction area 13, combined with the positioning parts set around the thickness reduction area 13, provides angular assistance to the MEA from the four corners, suppressing peripheral deformation. Thus, the MEA film deformation is suppressed through multi-angle coordinated cooperation from the circumferential direction and the four corner intersection directions. In the process of assembly, preparation and use, this reduces the possibility of MEA dimensional deformation, misalignment deviation and wrinkles, improves the overall tensile strength and structural stability of the MEA, and effectively resists the adverse effects caused by dimensional deformation. At the same time, this structure enables rapid and accurate assembly of the MEA and the anode diffusion layer 2, replacing the traditional operation method that relies on manual pressing and calibration, and systematically solves a series of problems such as sealing failure, MEA damage, assembly error and low production efficiency in traditional structures.

[0028] Understandably, the integral pad 1 has gas outlets (hydrogen outlet, oxygen outlet, and corresponding drainage pipes) for water electrolysis, water inlet outlets, water channels, gas collection channels, and other related structures, with the corresponding structures referencing existing technologies. For example, the integral pad 1 may have a flow guiding structure. A power supply is connected to the wire, allowing water to be introduced from the water outlet pipe, pass through the connecting holes in the integral pad 1, and enter the flow guiding structure. While passing through the flow guiding structure, the water permeates the anode titanium mesh 2 and the anode diffusion layer 3, undergoing an electrochemical reaction with the membrane electrode assembly 4. Oxygen is generated on one side of the membrane electrode assembly 4, and hydrogen is generated on the other side. Afterward, the oxygen and the remaining water after the reaction flow along the flow guiding structure into either the oxygen outlet pipe or the water outlet pipe, while the hydrogen generated on the other side flows along another set of flow guiding structures through the connecting holes on the integral pad 1 into the hydrogen outlet pipe for collection.

[0029] In some specific embodiments, the thickness reduction zone 11 has a longitudinal length of 0.1-50 mm along the elongated structure it is located in; the groove 12 has a groove depth of 0.1-2 mm, a groove width of 0.1-10 mm, and the center line of the groove is 1-15 mm away from the inner edge of the integral pad 1.

[0030] Specifically, optimizations are made for the differential pressure working environment. The thickness reduction zone 11 is designed to have a longitudinal length of 5-15mm along its elongated structure, allowing the cathode inner frame size to be precisely reduced by 5-15mm compared to the anode inner frame size. This precise dimensional difference design provides reliable protection for the MEA even with an assembly gap of ≤0.5mm between the gas diffusion layer and the gasket inner frame, preventing component damage caused by differential pressure and further ensuring the stability and service life of the electrolytic cell. Furthermore, the cell width is differentiated within the range of 3-6mm based on the effective area requirement of the thickness reduction zone 13, and the cell depth is preferably 0.6-0.7mm. The distance from the centerline of the cell to the inner edge of the integral pad 1 is 3-8mm. This suitable cell depth design effectively avoids displacement of the buffer stretching strip during the pressing process. Utilizing the large compressibility of the buffer stretching strip, it achieves [property protection] within the cell. While maintaining a high filling volume, sufficient deformation space is retained, which helps to enhance the effect of the buffer tension strip in alleviating the stress unevenness caused by the material difference between the integral pad 1 and the anode diffusion layer 3, as well as the uneven pressure changes on both sides of the MEA. This avoids irreversible creep deformation and thinning of the MEA due to local overpressure, reducing its risk of breakage. At the same time, it effectively inhibits the deformation and sealing failure of the MEA during pressing and use. In addition, by precisely controlling the position of the buffer tension strip, the porous sintered titanium layer, which is the anode diffusion layer 3, and the MEA can be placed in a reasonable and stable support position on the integral pad 1. This helps to balance the stress distribution of the porous sintered titanium layer and the MEA during assembly and use, further reducing the possibility of dimensional deformation, misalignment, and wrinkles in the MEA. This improves the overall tensile strength and structural stability of the MEA and effectively resists various adverse effects caused by dimensional deformation.

[0031] In some specific implementations, the compression rate of the buffer stretching strip is 5-50%, and the filling amount is 50-90%. Utilizing the buffer stretching strip's large compression deformation rate, a high filling amount is achieved within the groove while maintaining sufficient deformation space. This enhances the buffer stretching strip's ability to alleviate stress unevenness caused by material differences between the integral pad 1 and the anode diffusion layer 3, as well as uneven pressure changes on both sides of the MEA. This prevents irreversible creep deformation and thinning of the MEA due to localized overpressure, reducing its breakage risk. Simultaneously, it effectively suppresses MEA deformation and sealing failure during pressing and use.

[0032] In some specific embodiments, the integral pad 1 is made of one or more of polyetherimide, polysulfone, polytetrafluoroethylene, polyoxymethylene, and polyamide as raw materials, or the main structure of the integral pad 1 is made of one or more of polyetherimide, polysulfone, polytetrafluoroethylene, polyoxymethylene, and polyamide as raw materials, with some areas made of other materials. The raw materials include pure materials and modified materials. The rigid integral pad 1 enhances the support stability of the MEA through its high rigidity. The anode diffusion layer 3 is made of porous sintered titanium material. Its porous structure and rigid substrate provide appropriate micro-roughness to the surface, which not only enhances the mechanical support of the relatively soft MEA but also effectively suppresses the displacement problem of the MEA caused by interface slippage during the pressing and assembly process through surface roughness. However, since the integral pad is made of a rigid material while the anode diffusion layer is a porous sintered titanium layer, there are differences in hardness and deformability (such as differences in thermal expansion coefficients and compressive deformation resistance). During the pressing process, when the relatively flexible MEA is sandwiched in the middle, the inconsistent mechanical response between the different materials causes the MEA to bear uneven stress, which in turn leads to mechanical compression, local overpressure, and stress concentration, increasing the risk of irreversible creep deformation, thinning, or even breakage of the MEA, and also increasing the possibility of seal failure. To address this, the aforementioned method involves creating a groove 12 in the thickness reduction area 13 of the integral pad 1 and filling it with a buffer tension strip with a hardness closer to that of the MEA, which can improve the sealing performance during the pressing process. It provides excellent deformation coordination capabilities, effectively alleviating stress concentration caused by material differences and uneven pressure on both sides of the MEA, avoiding damage to the MEA caused by local overpressure, thereby improving its structural stability and sealing reliability. In addition, the porous sintered titanium layer itself has a high surface roughness, which can also play a certain role in anchoring and constraining the MEA, further suppressing its deformation during pressing and use. Through the more matched hardness characteristics between the buffer tension strip and the MEA, and the synergistic effect formed by the high roughness of the porous sintered titanium layer on both sides of the MEA membrane, it can effectively suppress the deformation, crack initiation and propagation of the MEA periphery, thereby improving the structural integrity and sealing durability of the MEA membrane.

[0033] In some specific embodiments, at least a portion of the thickness reduction region 11 is made from one or more of the following raw materials: rubber, polyurethane, resin, and silicone. These raw materials include both pure and modified forms. The buffer tension strip is made from one or more of the following raw materials: rubber, polyurethane, resin, and silicone. Examples of rubber materials include EPDM rubber, fluororubber, and silicone rubber; polyurethane materials include polyether-type polyurethane, polyester-type polyurethane, and bio-based polyurethane; resin materials include epoxy resin; and silicone materials include liquid silicone and solid silicone. The selection of these materials is not specifically limited. The contact area between the thickness reduction region 11 and the MEA can be made from the aforementioned flexible materials, or entirely from these materials, to reduce damage to the MEA.

[0034] In some specific embodiments, the groove 12 in the thickness reduction region 11 can be replaced by a protrusion (not shown in the figure). The protrusion can be triangular, semi-circular, elliptical, or irregularly curved, and is made of a flexible and deformable material, such as one or more of rubber, polyurethane, resin, and silicone. The material includes its pure form and modified form. This achieves a sealing connection with the MEA, and its function is similar to that of the groove and the buffer tension strip, which will not be elaborated here.

[0035] Please continue reading. Figure 1 and Figure 2 The present invention also provides a PEM electrolytic cell, including the above-mentioned integral pad 1 assembly, and an anode titanium mesh 2, an anode diffusion layer 3, an MEA, a cathode diffusion layer 5 and a cathode titanium mesh 6 sequentially stacked on the integral pad 1 assembly along the anode to cathode direction; the anode diffusion layer 3 and the cathode diffusion layer 5 are porous sintered titanium layers.

[0036] In some specific embodiments, an installation gap of 0.1-1 mm is formed between the outer periphery of the anode titanium mesh 2, the anode diffusion layer 3, and the MEA and the thickness reduction zone 13 of the integral pad 1. This reasonable installation gap not only facilitates the smooth assembly of each functional layer during installation and reduces installation difficulty, but also effectively reduces the stringent requirements on the machining accuracy of the anode titanium mesh 2, the anode diffusion layer 3, and the MEA by appropriately relaxing assembly tolerances. In traditional single-sided high-pressure hydrogen production structures, to avoid the risk of MEA breakage due to interference fit or uneven stress under unilateral back pressure, the machining tolerances of the anode titanium mesh 2, the anode diffusion layer 3, and the MEA usually need to be strictly controlled within 0.1 mm. However, by adopting the optimized integral pad 1 structure, combined with the synergistic positioning and support of the positioning component 13, the dimensional deformation of the MEA that may occur during assembly and operation can be reduced. Problems such as misalignment, deviation, and wrinkles can be addressed by expanding the allowable tolerance range to 0.5mm (i.e., reducing the accuracy requirement by about 5 times). This not only significantly reduces the processing difficulty of the anode titanium mesh 2, anode diffusion layer 3, and MEA, but also effectively improves assembly efficiency. In addition, by appropriately increasing the width of the installation gap, mechanical extrusion or friction damage to the anode titanium mesh 2, anode diffusion layer 3 (especially thin-walled and easily damaged parts such as sintered titanium plates) and MEA can be avoided during the pressing process of the integral pad 1. This reduces the risk of structural damage caused by uneven pressure distribution, thermal expansion and contraction, and other factors, thereby further improving the operational stability and service life of MEA and related functional components.

[0037] In some specific embodiments, when the integral pad 1 assembly is stacked and assembled with the anode titanium mesh 2, anode diffusion layer 3, MEA, cathode diffusion layer 5, and cathode titanium mesh 6, the applied pressing pressure is 0-3 MPa. By precisely controlling the pressure during this pressing process, the compression deformation of the buffer tension strip can be effectively controlled, ensuring that it is compressed uniformly and moderately within the design allowable range. This avoids problems such as unexpected dimensional deformation, misalignment, and wrinkles in the MEA during assembly due to local over- or under-pressure. This pressure control not only helps to ensure the geometric accuracy and interface consistency of the MEA during the pressing process, but also effectively improves the overall tensile strength and structural stability of the MEA, reducing the risk of performance degradation caused by assembly stress or structural deformation.

[0038] In some specific embodiments, the porous sintered titanium layer has a porosity of 10-50%, a thickness of 0.5-2 mm, and a density of 3.0-4.0 g / cm³. 3 Furthermore, the deformation of the porous sintered titanium layer is 1-20%. By precisely controlling the porosity, thickness, and density of the sintered titanium layer, the fluid gradient expansion performance is optimized. The porosity setting of the sintered titanium layer, particularly at the integral pad 1, helps regulate the surface roughness of the porous structure. Reasonable control of surface roughness not only inhibits MEA (soft membrane) displacement during pressing but also effectively addresses potential problems such as dimensional deformation, misalignment, and wrinkles during pressing assembly and use, thereby improving the overall tensile strength and structural stability of the MEA and effectively resisting adverse effects caused by dimensional deformation. Furthermore, by controlling the porosity of the sintered titanium layer and the wire diameter of the titanium mesh layer, and based on the density differences of different functional layers on a single surface area, a gradual and differentiated pore structure is formed. This allows the sintered titanium layer and the titanium mesh layer to distribute the pressure they bear in different directions under pressure, achieving a uniform pressure distribution. This facilitates a more balanced force on the MEA, further reducing the risk of dimensional deformation, misalignment, and wrinkles, enhancing the overall tensile strength and structural stability of the MEA, and effectively resisting the adverse effects caused by dimensional deformation. In some specific embodiments, the titanium mesh wire diameter of the anode titanium mesh 2 and the cathode titanium mesh 6 is 0.3-1.2 mm, the thickness is 0.5-2 mm, and the density is 1.5-2.0 g / cm³. 3Furthermore, the deformation after molding is 5-10%. The titanium mesh layer possesses the same or similar deformation capacity as the sintered titanium layer. In particular, the titanium mesh layer uses the same material as the sintered titanium layer (unlike stainless steel mesh, etc.), which not only helps to reduce costs but also allows for smaller deformation differences when the two are used together (under conditions such as uneven stress and temperature changes). This results in a more stable and rigid MEA support structure, further reducing the possibility of dimensional deformation, misalignment, and wrinkles during MEA assembly and operation. This improves the overall tensile strength and structural stability of the MEA, effectively resisting various adverse effects caused by dimensional deformation.

[0039] Furthermore, the PEM electrolyzer employs a zero-gap structure design. During the pre-assembly stage, the initial thickness of the gas diffusion layer (titanium mesh and porous sintered titanium layer) must be greater than the thickness of the integral pad 1, thereby ensuring that the gas diffusion layer can undergo controllable elastic or plastic deformation during the press-fitting process, ultimately achieving zero-gap close contact between it and the membrane electrode (MEA).

[0040] In some specific implementations, the outer periphery of the MEA is sealed with polyethylene naphthalate (PEN) material on one side, with a sealing width of 5-50mm. Specifically, addressing the issue of the large effective area of ​​the product and the susceptibility of the MEA contact surface to dimensional deformation due to water absorption or evaporation caused by changes in ambient temperature and humidity (which can lead to misalignment deviations and wrinkles of 1-3mm in extreme cases), the traditional double-sided sealing structure has been innovatively optimized into a single-sided sealing design. While ensuring that the overall strength of the sealing meets the usage requirements, this not only simplifies the sealing process and significantly shortens the process flow time, but also reduces the amount of sealing material used, thereby effectively controlling manufacturing costs and improving production economy. At the same time, the introduction of PEN material enhances the overall tensile strength and structural stability of the MEA, effectively suppressing various adverse effects that may be caused by dimensional deformation.

[0041] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integral pad assembly for a PEM electrolytic cell, characterized in that, include: An integral pad (1) with a stepped structure, wherein a groove (12) is formed in the thickness reduction area (11) of the integral pad (1), and a buffer tension strip is embedded in the groove (12); The thickness reduction area (11) is provided with several positioning elements (13) around its periphery for circumferentially limiting the membrane electrode assembly (4).

2. The integral pad assembly for PEM electrolytic cells according to claim 1, characterized in that, The thickness reduction zone (11) has a longitudinal length of 0.1-50 mm along its length; the groove (12) has a groove depth of 0.1-2 mm, a groove width of 0.1-10 mm, and the groove centerline is 1-15 mm from the inner edge of the integral pad (1).

3. The integral pad assembly for PEM electrolytic cells according to claim 1, characterized in that, The compression rate of the buffer stretching strip is 5-50%, and the filling amount is 50-90%.

4. The integral pad assembly for PEM electrolytic cells according to claim 1, characterized in that, The integral pad (1) is made of one or more of the following raw materials: polyetherimide, polysulfone, polytetrafluoroethylene, polyoxymethylene, and polyamide. The raw materials include their pure materials and modified materials. At least a portion of the thickness reduction area (11) is made of one or more of the following raw materials: rubber, polyurethane, resin, and silicone. The raw materials include their pure materials and modified materials.

5. The integral pad assembly for PEM electrolytic cells according to claim 1, characterized in that, A protrusion is provided in the thickness reduction area (11) to replace the groove (12).

6. A PEM electrolytic cell, characterized in that, It includes the integral pad assembly as described in any one of claims 1-5, and the anode titanium mesh (2), anode diffusion layer (3), membrane electrode assembly (4), cathode diffusion layer (5) and cathode titanium mesh (6) sequentially stacked on the integral pad assembly along the anode to cathode direction; the anode diffusion layer (3) and the cathode diffusion layer (5) are porous sintered titanium layers.

7. The PEM electrolytic cell according to claim 6, characterized in that, An installation gap of 0.1-1 mm is formed between the outer periphery of the anode titanium mesh (2), the anode diffusion layer (3) and the membrane electrode assembly (4) and the thickness reduction area (11) of the integral pad (1).

8. The PEM electrolytic cell according to claim 6, characterized in that, When the integral pad (1) assembly is stacked with the anode titanium mesh (2), anode diffusion layer (3), membrane electrode assembly (4), cathode diffusion layer (5) and cathode titanium mesh (6), the applied pressing pressure is 0-3 MPa.

9. The PEM electrolytic cell according to claim 6, characterized in that, The porous sintered titanium layer has a porosity of 10-50%, a thickness of 0.5-2 mm, and a density of 3.0-4.0 g / cm³. 3 Furthermore, the deformation of the porous sintered titanium layer is 1-20%.

10. The PEM electrolytic cell according to claim 6, characterized in that, The titanium mesh wires of the anode titanium mesh (2) and the cathode titanium mesh (6) have a diameter of 0.3-1.2 mm, a thickness of 0.5-2 mm, and a density of 1.5-2.0 g / cm³. 3 And the deformation after molding is 5-10%.

11. The PEM electrolytic cell according to claim 6, characterized in that, The outer periphery of the membrane electrode assembly (4) is sealed with polyethylene naphthalate (PEN) material on one side, with a sealing width of 5-50 mm.

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