PEM electrolyzed water membrane electrode assembly and assembling method
By optimizing the material and pore size of the gas diffusion layer, and combining it with precise assembly methods, the problem of poor bonding between the catalyst layer and the diffusion layer was solved, thus achieving efficient operation and improved stability of the PEM water electrolysis system.
Patent Information
- Application Number
- CN202511440893.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-10
- Publication Date
- 2026-01-16
AI Technical Summary
In existing PEM water electrolysis systems, the interface between the catalyst layer and the diffusion layer is not tightly bonded, resulting in high contact resistance, which leads to insufficient conductivity and transport capacity, affecting overall performance and operational stability.
Carbon paper or titanium felt of specific thickness and pore size is used as the cathode gas diffusion layer, and platinum-plated titanium felt is used as the anode gas diffusion layer. Precise assembly methods are used to ensure close contact between the layers, including torque control for initial tightening, intermediate tightening, and final tightening. The pore structure of the catalyst layer is optimized to improve electron and gas transport efficiency.
It significantly reduces battery operating voltage, improves electrolysis efficiency, extends system lifespan, enhances component bonding strength, and improves water and air transport efficiency.
Smart Images
Figure CN121344645A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of new energy and hydrogen energy technology, specifically relating to membrane electrode assemblies in water electrolysis hydrogen production technology, and more specifically, to a membrane electrode assembly and assembly method for PEM water electrolysis. Background Technology
[0002] Proton exchange membrane (PEM) water electrolysis is a key technology for achieving green hydrogen production, boasting advantages such as high operating current density, high hydrogen purity, and fast dynamic response. It is particularly suitable for stable operation under fluctuating output conditions from renewable energy sources like wind and solar power. Therefore, this technology is widely considered one of the most promising green hydrogen production methods currently available. The core functional component of a PEM electrolyzer is the MEA, whose basic structure includes an anode catalyst layer, a proton exchange membrane, and a cathode catalyst layer. During electrolysis, the anode catalyst layer performs the oxygen evolution reaction (OER), while the cathode catalyst layer performs the hydrogen evolution reaction (HER). The system drives the electrochemical reactions continuously by applying an external voltage (typically around 2.0 V) to the electrodes of the electrolyzer.
[0003] As a typical electrochemical reaction system, the energy conversion efficiency and service life of a PEM electrolyzer are closely related to its overall resistance characteristics. Lower system internal resistance helps reduce the operating voltage, decrease the energy consumption required for hydrogen production per unit, and significantly alleviate material corrosion problems that may occur under high voltage conditions. Therefore, the interfacial contact between functional layers must have excellent bonding to minimize contact resistance and improve overall performance. In mainstream PEM electrolyzers, the gas diffusion layer (GDL) often uses conductive metal materials such as titanium sintered plates and titanium felt to transport reactant gases, current, and support structures. These porous materials play important structural and functional roles in the reaction process. However, the interfacial connection between traditional GDL materials and the catalyst layer is generally insufficient, mainly due to the following factors: first, the material itself has limited conductivity; second, titanium materials easily form a dense oxide layer on the surface, increasing contact resistance; and third, the roughness of the porous structure is not well matched with the surface of the catalyst layer, resulting in poor local contact, thus affecting the overall working efficiency and long-term stability of the MEA.
[0004] Currently, commonly used GDL materials are mainly titanium, but titanium itself has relatively poor electrical conductivity, and its surface easily forms a dense titanium oxide layer in air or electrolytic environments, further weakening electron conduction and increasing interfacial resistance. In addition, the significant difference in pore structure between the titanium-based gas diffusion layer and the catalyst layer significantly affects the interfacial bonding effect. Taking titanium felt as an example, its average pore size is typically on the order of hundreds of micrometers, while the pore size of the catalyst layer is only a few micrometers, a difference of up to two orders of magnitude. This mismatch in pore structure results in limited contact area and loose bonding between the catalyst layer and the diffusion layer, leading to discontinuous electron transport paths and increased interfacial contact resistance. Furthermore, the catalyst layer itself suffers from small pore size, low porosity, and poor surface hydrophilicity, further limiting the effective transport of generated gases (H2, O2), resulting in significant polarization and energy loss. In summary, the following technical bottlenecks are commonly found in existing PEM water electrolysis systems: First, the interface between the catalyst layer and the diffusion layer is not tightly bonded, resulting in high contact resistance; second, the conductivity and transport capacity of the PTL are insufficient, limiting the overall performance and operational stability of the PEM electrolyzer. Summary of the Invention
[0005] The purpose of this invention is to solve the above-mentioned problems and provide a membrane electrode assembly and assembly method for PEM water electrolysis system. The membrane electrode assembly enhances the bonding strength of the assembly, improves the water-air transport efficiency, improves the performance of PEM water electrolysis system, and significantly extends its service life.
[0006] Therefore, a first aspect of the present invention provides a membrane electrode assembly for PEM water electrolysis, the membrane electrode assembly for PEM water electrolysis comprising a cathode gas diffusion layer, a cathode catalyst layer, a proton exchange membrane layer, an anode catalyst layer, and an anode gas diffusion layer arranged sequentially. The thickness of the cathode gas diffusion layer is 400 μm-450 μm; the material of the cathode gas diffusion layer is carbon paper or titanium felt, and the pore size is 30 μm-40 μm. The thickness of the anode gas diffusion layer is 300 μm-400 μm; the material of the anode gas diffusion layer is platinum-plated titanium felt with a pore size of 25 μm-35 μm.
[0007] In this invention, the cathode catalyst layer typically supports a hydrogen evolution reaction catalyst, commonly a platinum-based catalyst, to promote the reduction of hydrogen ions to generate hydrogen gas. The anode catalyst layer supports an oxygen evolution reaction catalyst, commonly an iridium-based, ruthenium-based, or oxide thereof; sometimes alloy or carrier-supported catalysts are also used. The cathode gas diffusion layer has a thickness of 400 μm-450 μm, is made of carbon paper or titanium felt, and has a pore size of 30 μm-40 μm, which is beneficial for gas diffusion and water management, improves durability and mechanical support, and is suitable for gas discharge and liquid water management under high current density. The anode gas diffusion layer has a thickness of 300 μm-400 μm, is made of platinum-plated titanium felt, and has a pore size of 25 μm-35 μm. The titanium felt is corrosion-resistant, and the platinum plating improves conductivity, making it suitable for high oxidation potential environments and improving the stability and lifespan of the anode under harsh electrochemical environments. This membrane electrode assembly is suitable for PEM water electrolysis hydrogen production systems, and its working principle is as follows: Anode (oxidation reaction): 2H₂O → 4H + +4e - +O2↑ Cathode (reduction reaction): 4H + +4e - →2H2↑ Proton exchange membranes (such as the Nafion series): conduct H+ + It blocks electrons and gases, maintaining the reaction zone.
[0008] According to one specific embodiment of the present invention, the cathode catalyst layer and the anode catalyst layer can be directly coated on both sides of the proton exchange membrane, and then stacked with other layers to form a membrane electrode assembly; or first form a "catalyst layer-gas diffusion layer" composite with the gas diffusion layer, and then stacked with other layers to form a membrane electrode assembly.
[0009] The most common cathode gas diffusion layer thickness in commercially available products is between 200-350 μm, with an average pore size typically between 15-25 μm. The mainstream anode gas diffusion layer thickness in commercially available products is between 500-1000 μm, with an average pore size typically between 10-20 μm. This invention improves the voltage performance of the membrane electrode assembly by making corresponding improvements to the thickness and pore size.
[0010] To further improve the voltage performance of the membrane electrode assembly, the preferred solution is: The thickness of the cathode gas diffusion layer is 400 μm-440 μm; the pore size of the cathode gas diffusion layer is 30 μm-37 μm; the thickness of the anode gas diffusion layer is 300 μm-370 μm; and the pore size of the anode gas diffusion layer is 25 μm-31 μm.
[0011] As the optimal solution, the above-mentioned membrane electrode assembly for PEM water electrolysis is: The thickness of the cathode gas diffusion layer is 400 μm-420 μm; the pore size of the cathode gas diffusion layer is 30 μm-34 μm; the thickness of the anode gas diffusion layer is 300 μm-340 μm; and the pore size of the anode gas diffusion layer is 25 μm-28 μm.
[0012] In this invention, the proton exchange membrane is a Nafion membrane, a Formarium membrane, a Gore membrane, or an Asahi Glass membrane. For example, perfluorosulfonic acid membranes produced by DuPont or Chemours have extremely high proton conductivity and excellent chemical and thermal stability; Formarium membranes, from the Voith Group, are high-performance perfluorosulfonic acid membranes with excellent chemical stability and mechanical strength; they are suitable for high-temperature and highly corrosive environments, and some models have improved hydrophilicity and gas barrier properties; they are suitable for industrial-grade electrolyzers; Gore membranes, based on ePTFE (expanded polytetrafluoroethylene) reinforced perfluorosulfonic acid composite membranes, have excellent mechanical strength, puncture resistance, and gas barrier properties, significantly reducing hydrogen permeability; they are suitable for high-pressure, high-power-density electrolysis systems and are a popular choice for high-end electrolyzers; and Asahi Glass membranes, produced by Asahi Glass Co., Ltd., are also suitable.
[0013] As a preferred embodiment, in the aforementioned PEM membrane electrode assembly for water electrolysis, the cathode catalyst layer is made of platinum (Pt) or platinum-carbon (Pt / C). Platinum (Pt) is currently recognized as the best catalyst for hydrogen evolution reaction, exhibiting extremely low overpotential and high exchange current density; it is typically deposited as a thin layer on the catalyst layer or directly supported on the membrane. Platinum-carbon catalyst (Pt / C) is the most commonly used hydrogen evolution reaction catalyst in industry, achieving a balance between catalytic activity and cost by highly dispersing nano-sized Pt particles on a carbon material with a high specific surface area.
[0014] As a preferred embodiment, the above-mentioned membrane electrode assembly for PEM water electrolysis satisfies the following requirements: The pore size of the cathode catalyst layer is 50 μm-200 μm. This range ensures sufficient catalyst loading and reactive sites, while avoiding excessive thickness that could increase ion transport resistance or hinder gas diffusion.
[0015] The thickness of the cathode catalyst layer is 5 μm-20 μm. This pore size range is mainly for the porous structure inside the catalyst layer or the connecting pores with the adjacent gas diffusion layer, which is conducive to the escape of reaction gas, the discharge of water and the transmission of electrons, and avoids local water accumulation or catalyst shedding.
[0016] As a preferred embodiment, in the above-mentioned membrane electrode assembly for PEM water electrolysis, the anode catalyst layer is made of iridium oxide (IrO2) or ruthenium iridium oxide.
[0017] As a preferred embodiment, the above-mentioned membrane electrode assembly for PEM water electrolysis satisfies the following requirements: The pore size of the anode catalyst layer is 50 μm-200 μm; The thickness of the anode catalyst layer is 5 μm-20 μm.
[0018] The thickness and pore size design of the anode catalyst layer are also aimed at balancing catalytic activity, gas transport, electron conduction, and structural stability. An appropriate pore structure facilitates the timely escape of oxygen, avoids bubble blockage and local high pressure, and maintains a tight bond between the catalyst layer and the proton exchange membrane.
[0019] A second aspect of the present invention provides a method for assembling the above-described membrane electrode assembly for PEM water electrolysis, the assembly method comprising: Assemble the membrane electrode in the following order: gas diffusion layer, cathode catalyst layer, proton exchange membrane layer, anode catalyst layer, and anode gas diffusion layer. During assembly, ensure that the cathode gas diffusion layer and anode gas diffusion layer are aligned and fully cover the membrane electrode, and leave the edge area of the membrane electrode to cover the sealing ring. After covering the anode plate, install gaskets and nuts at multiple holes equidistantly arranged along the edge of the anode plate. First, initially tighten the nuts to eliminate gaps between components and ensure initial contact of the gaskets. After initial tightening, use a torque wrench to apply constant pressure to the holes in opposite positions for intermediate tightening, uniform pre-compression, and avoid stress concentration at single points. Finally, tighten the holes in opposite positions to ensure tight contact between all interfaces without displacement or stress concentration, achieving the designed sealing pressure.
[0020] As a preferred embodiment, the assembly method of the above-mentioned membrane electrode assembly for PEM water electrolysis is as follows: The initial tightening pressure is 0.35-0.55 MPa, the medium tightening pressure is 0.85-1.0 MPa, and the final tightening pressure is 1.0-1.4 MPa. The target torque for initial tightening is 0.55-0.65 N, the target torque for medium tightening is 0.95-1.05 N, and the target torque for final tightening is 1.3-1.4 N.
[0021] As a preferred embodiment, the assembly method of the membrane electrode assembly for PEM water electrolysis described above further includes, before assembly: cleaning the surface of the components with a lint-free cloth and / or ethanol to ensure that there are no impurities, particles, or oil stains.
[0022] Compared with the prior art, the present invention has at least the following beneficial effects: The membrane electrode assembly for water electrolysis of the present invention is applicable to different types of proton exchange membranes, and can significantly reduce battery operating voltage and improve electrolysis efficiency.
[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description
[0024] Figure 1 A schematic diagram of a specific embodiment of a membrane electrode assembly for PEM water electrolysis is shown.
[0025] Figure 2 An assembly diagram of a specific embodiment of a membrane electrode assembly for PEM water electrolysis is shown.
[0026] Explanation of reference numerals in the attached figures: 1-Anode plate, 2-Anode gas diffusion layer, 3-Anode catalyst layer, 4-Cathode catalyst layer, 5-Cathode gas diffusion layer, 6-Cathode plate, 7-Proton exchange membrane layer. Detailed Implementation
[0027] The following description provides numerous specific details to offer a more thorough understanding of the technical solutions provided by this invention. However, it will be apparent to those skilled in the art that the technical solutions provided by this invention can be implemented without one or more of these details.
[0028] Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.
[0029] Examples 1-6 Examples 1-6 all provide a membrane electrode assembly for PEM water electrolysis.
[0030] refer to Figure 1 , Figure 2 The assembly method of the membrane electrode assembly for PEM water electrolysis in Examples 1-6 includes: Clean the surfaces of the bipolar plates and membrane electrode assemblies using a lint-free cloth and ethanol to ensure they are free of impurities, particles, and oil. On the cathode plate 6, assemble the cathode gas diffusion layer 5, cathode catalyst layer 4, proton exchange membrane layer 7, anode catalyst layer 3, and anode gas diffusion layer 2 from bottom to top. Before assembly, the cathode catalyst layer 4 and anode catalyst layer 3 are pre-placed on the proton exchange membrane layer 7. During assembly, ensure that the cathode gas diffusion layer 5 and anode gas diffusion layer 2 are aligned and fully cover the membrane electrode, leaving the edge of the membrane electrode to cover the sealing ring. After placing the anode plate 1, place gaskets and nuts at the eight corners of the anode plate 1. First, initially tighten the nuts to eliminate component gaps and ensure initial contact of the gaskets. After initial tightening, use a torque wrench to apply constant pressure to the corresponding holes for intermediate tightening, uniform pre-pressurizing to avoid stress concentration at single points. Finally, tighten the corresponding holes to ensure tight contact at all interfaces without misalignment or stress concentration, achieving the designed sealing pressure. The initial tightening pressure is 0.35-0.55 MPa, the medium tightening pressure is 0.85-1.0 MPa, and the final tightening pressure is 1.0-1.4 MPa. The target torque for initial tightening is 0.6 N, the target torque for medium tightening is 1.0 N, and the target torque for final tightening is 1.35 N. Specifically, the first step is to apply the first set of diagonal torques simultaneously using a torque wrench at diagonal positions (e.g., upper left to lower right is one pair, upper right to lower left is another pair). The second step is to apply the first set of opposite-side torques, typically to the bolts adjacent to the first set, also simultaneously, applying a low torque of 0.6 N·m. The third step is to apply the second set of diagonal and opposite-side torques, simultaneously with the first set, applying a medium torque of 1 N·m. The fourth step is to apply the third set of diagonal and opposite-side torques, simultaneously with the first and second sets, applying a final torque of 1.35 N. N·m, ultimately achieving the required clamping force to ensure consistent load on all bolts.
[0031] The membrane electrode assemblies for PEM water electrolysis in Examples 1-6 meet the following requirements: The cathode catalyst layer is made of platinum carbon with a pore size of 0.05 mm and a thickness of 0.005 mm.
[0032] The anode catalyst layer is made of iridium oxide, with a pore size of 0.05 mm and a thickness of 0.005 mm.
[0033] For details of the differences, please refer to Table 1 and Table 2.
[0034] Comparative Examples 1-6 For details of the differences from the embodiments, please refer to Tables 1 and 2.
[0035] The thickness, pore size, and voltage performance of the products obtained in the examples and comparative examples were tested, and the results are as follows: Table 1
[0036] Table 2
[0037] As can be seen from Tables 1 and 2, when the cathode gas diffusion layer meets the requirements of specific pore size + specific thickness, and the anode gas diffusion layer meets the requirements of specific pore size + specific thickness, the performance of the membrane electrode assembly is significantly improved.
[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A membrane electrode assembly for PEM electrolysis of water, characterized by, The PEM water electrolysis membrane electrode assembly comprises, in sequence, a cathode gas diffusion layer, a cathode catalytic layer, a proton exchange membrane layer, an anode catalytic layer, and an anode gas diffusion layer. The thickness of the cathode gas diffusion layer is 400-450 μm, and the material of the cathode gas diffusion layer is carbon paper or titanium felt with a pore size of 30-40 μm. The thickness of the anode gas diffusion layer is 300-400 μm, and the material of the anode gas diffusion layer is platinum-coated titanium felt with a pore size of 25-35 μm.
2. The PEM water electrolysis membrane electrode assembly according to claim 1, wherein the thickness of the cathode gas diffusion layer is 400-440 μm, and the pore size of the cathode gas diffusion layer is 30-37 μm. The thickness of the anode gas diffusion layer is 300-370 μm, and the pore size of the anode gas diffusion layer is 25-31 μm.
3. The PEM water electrolysis membrane electrode assembly according to claim 2, wherein the thickness of the cathode gas diffusion layer is 400-420 μm, and the pore size of the cathode gas diffusion layer is 30-34 μm. The thickness of the anode gas diffusion layer is 300-340 μm, and the pore size of the anode gas diffusion layer is 25-28 μm. The proton exchange membrane layer is a Nafion membrane, a Forma membrane, a Gore membrane, or an Asahi membrane. The material of the cathode catalytic layer is platinum or platinum-carbon.
4. The PEM electrolyzer membrane electrode assembly of claim 1, wherein, 6. The PEM water electrolysis membrane electrode assembly according to claim 1, wherein the pore size of the cathode catalytic layer is 50-200 μm, and the thickness of the cathode catalytic layer is 5-20 μm.
5. The PEM electrolyzer membrane electrode assembly of claim 1, wherein, The material of the anode catalytic layer is iridium oxide or ruthenium-iridium oxide.
8. The PEM water electrolysis membrane electrode assembly according to claim 1, wherein the pore size of the anode catalytic layer is 50-200 μm, and the thickness of the anode catalytic layer is 5-20 μm. The assembly method comprises: The components are assembled in the order of the cathode gas diffusion layer, the cathode catalytic layer, the proton exchange membrane layer, the anode catalytic layer, and the anode gas diffusion layer, and during the assembly, the cathode gas diffusion layer is aligned with the anode gas diffusion layer and fully covers the membrane electrode, and the membrane electrode leaves a region that covers the sealing ring; 7. The PEM electrolyzer membrane electrode assembly of claim 1, wherein, After the anode plate is covered, gaskets and nuts are installed at the positions of multiple equidistant holes at the edge of the anode plate, the nuts are initially tightened first to eliminate the gap between the components and ensure that the gaskets are initially in contact; the nuts are then uniformly pre-pressed by applying constant pressure to the opposite holes using a torque wrench to avoid single-point stress concentration; finally, the opposite holes are finally tightened to ensure that the interfaces are in close contact and do not produce deviation or stress concentration, and the designed sealing pressure is achieved.
10. The assembly method of the PEM water electrolysis membrane electrode assembly according to claim 9, wherein 9. The assembling method of the PEM electrolytic water cell membrane electrode assembly as claimed in any one of claims 1 to 8, characterized in that, The initial tightening pressure is 0.35-0.55 MPa, the intermediate tightening pressure is 0.85-1.0 MPa, and the final tightening pressure is 1.0-1.4 MPa; The initial target torque is 0.55-0.65 N, the intermediate target torque is 0.95-1.05 N, and the final target torque is 1.3-1.4 N.