Diffusion layer, membrane electrode assembly and hydrogen production device
By arranging a covering at the edge of the diffusion layer, the problem of the sharp edge of the diffusion layer puncturing the proton exchange membrane is solved, thereby improving the safety and stability of the hydrogen production device.
Patent Information
- Application Number
- CN202422609664.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-10-28
AI Technical Summary
The sharp edges of the diffusion layer can easily cause penetrating damage to the proton exchange membrane during the assembly process, leading to leakage problems and affecting the safety of the hydrogen production device.
A covering is provided at the edge area of the diffusion layer. A recess is formed in the edge area and the covering is injection-molded therein. The covering is made of polyphenylene sulfide, polyetherimide, EPDM rubber, etc., to prevent sharp edges from directly contacting the proton exchange membrane.
This effectively avoids perforation of the proton membrane by cuts or burrs on the edge of the diffusion layer, thereby improving the safety and operational stability of the hydrogen production device.
Smart Images
Figure CN223304560U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of hydrogen production, and in particular to a diffusion layer, a membrane electrode assembly, and a hydrogen production device. Background Art
[0002] The membrane electrode assembly (MEA) of a proton exchange membrane electrolyzer typically consists of four parts: the proton exchange membrane, the catalyst layer, the diffusion layer, and the frame. The diffusion layer is typically made of titanium felt, which contacts the proton exchange membrane on one side and the electrode flow field on the other. Fluid transfer occurs through the gaps between the titanium fibers within, increasing the contact area between the fluid and the catalyst.
[0003] When the diffusion layer and the proton exchange membrane come into contact, the cut edges of the titanium felt inevitably develop sharp cuts and titanium fiber burrs, which can easily penetrate the membrane. This is especially true during the compression process during assembly. These cuts and titanium fiber burrs can become compressed and embedded in the membrane, potentially puncturing it instantly or penetrating it after prolonged shearing. Both of these processes can cause perforation of the membrane, leading to cross-contamination and potentially causing safety issues such as burnout. Utility Model Content
[0004] The embodiments of the present application provide a diffusion layer, a membrane electrode assembly, and a hydrogen production device, which are intended to cover or wrap the sharp edges of the diffusion layer to avoid leakage problems caused by perforation of the proton exchange membrane.
[0005] An embodiment of the present application provides a diffusion layer, the diffusion layer comprising:
[0006] a diffuser body having a middle region and an edge region disposed around the middle region;
[0007] a covering member, wherein the covering member covers at least the edge region of one side of the diffusion body along the thickness direction of the diffusion layer;
[0008] Wherein, the edge area of at least one side of the diffuser body is provided with a recessed portion, and the covering component is provided in the recessed portion.
[0009] In a possible design, along the thickness direction of the diffusion layer, the surface of the covering member is flush with the surface of the middle region.
[0010] In a possible design, along the thickness direction of the diffusion layer, the thickness of the edge region is 85% to 98% of the thickness of the middle region.
[0011] In a possible design, along a direction perpendicular to the thickness direction of the diffusion layer, the outer edge of the covering member is aligned with the outer edge of the recessed portion; or,
[0012] Along a direction perpendicular to the thickness direction of the diffusion layer, the outer edge of the covering member extends beyond the outer edge of the recessed portion.
[0013] In a possible design, along the thickness direction of the diffusion layer, when the covering member covers the edge region of one side of the diffusion body, the covering member is used to contact the proton exchange membrane.
[0014] In a possible design, the diffuser body is titanium felt, and the edge region is formed into the recessed portion by rolling.
[0015] In a possible design, the covering part is injection molded on the recessed portion.
[0016] In a possible design, the covering member is made of one of polyphenylene sulfide, polyetherimide, EPDM rubber, and fluororubber.
[0017] In a second aspect, an embodiment of the present application provides a membrane electrode assembly, the membrane electrode assembly comprising:
[0018] Proton exchange membrane;
[0019] The diffusion layer is the diffusion layer described above, and the side of the diffusion layer provided with the covering member is in contact with the proton exchange membrane.
[0020] In a third aspect, an embodiment of the present application provides a hydrogen production device, comprising:
[0021] Plates;
[0022] Membrane electrode assembly, the electrode plate and the membrane electrode assembly are stacked, and the membrane electrode assembly is the membrane electrode assembly described above.
[0023] In the embodiment of the present application, a covering is provided at the edge area of the diffusion layer to cover or wrap the sharp edge of the diffusion layer, thereby avoiding perforation of the proton membrane due to cuts or burrs on the edge of the diffusion layer, thereby avoiding leakage problems and effectively improving the safety of the hydrogen production device.
[0024] At the same time, in the embodiment of the present application, a recess is provided in the edge area of the diffuser body, and the covering is provided in the recess, so as to prevent the covering from protruding from the diffuser layer along the thickness direction of the diffuser layer to cause interference and affect subsequent assembly.
[0025] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a schematic structural diagram of the diffusion layer provided in this application;
[0027] Figure 2 This is a schematic diagram of a diffusion body provided in this application in one embodiment;
[0028] Figure 3 This is a schematic diagram of another embodiment of the diffusion body provided by the present application;
[0029] Figure 4 A schematic cross-sectional view of a diffusion layer provided in this application in one embodiment;
[0030] Figure 5 A schematic cross-sectional view of another embodiment of the diffusion layer provided in this application;
[0031] Figure 6 A schematic diagram of a concave portion formed by rolling one side of the diffuser body provided in this application;
[0032] Figure 7 A schematic diagram of forming a concave portion by rolling on both sides of the diffuser body provided in this application;
[0033] Figure 8 A schematic diagram of the injection mold provided in this application;
[0034] Figure 9 This is a schematic cross-sectional view of an embodiment of the injection mold provided in this application;
[0035] Figure 10 This is a schematic cross-sectional view of another embodiment of the injection mold provided in this application.
[0036] Reference numerals:
[0037] 1-Diffusion layer;
[0038] 11-diffusion body;
[0039] 111-middle area;
[0040] 112-marginal area;
[0041] 112a-recessed portion;
[0042] 12- covering piece;
[0043] 2- roller;
[0044] 3-Injection mold;
[0045] 31-Glue injection port.
[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION
[0047] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0048] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0049] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.
[0050] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.
[0051] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described based on the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also be indirectly connected to the other element "on" or "under" through an intermediate element.
[0052] This embodiment provides a hydrogen production device, which includes a stacked membrane electrode assembly, a plate and a seal. The plate and the membrane electrode assembly are stacked, and the seal seals hydrogen and oxygen in independent closed areas. Specifically, the hydrogen production device uses a membrane electrode assembly as a solid electrolyte and uses pure water as a raw material for hydrogen production by electrolysis of water. When the hydrogen production device is in operation, water molecules undergo an oxidation reaction on the anode side, lose electrons, and generate oxygen and protons. Subsequently, the electrons are transferred to the cathode through an external circuit. Under the action of the electric field, the protons are conducted to the cathode through the membrane electrode assembly, and a reduction reaction occurs on the cathode side to obtain electrons to generate hydrogen. The hydrogen and oxygen after the reaction will be collected and transported through the anode and cathode plates.
[0053] Furthermore, the membrane electrode assembly includes a proton exchange membrane, a catalyst layer (a cathode catalyst layer and an anode catalyst layer) and a diffusion layer (a cathode diffusion layer and an anode diffusion layer), the catalyst layer is arranged on both sides of the proton exchange membrane, and the diffusion layer is arranged on the side of the catalyst layer away from the proton exchange membrane layer.
[0054] Among them, the diffusion layer usually uses titanium-based porous materials, which not only have good conductivity and mechanical strength, but also can provide a uniform gas diffusion path, thereby improving electrolysis efficiency and gas production.
[0055] For example, traditional diffusion layers use titanium felt cut to a fixed size (generally the size of the plate reaction area) and placed between the proton exchange membrane and the plate. The cut edges of the titanium felt inevitably have sharp cuts and titanium fiber burrs, which can easily penetrate the proton exchange membrane, causing cross-leakage and other safety issues such as burns.
[0056] To this end, this embodiment provides a diffusion layer to solve the above technical problems. The following will describe in detail possible structures of the diffusion layer with reference to the accompanying drawings.
[0057] like Figure 1 The figure shows a schematic diagram of a diffusion layer 1, which includes a diffuser body 11 and a covering member 12. The diffuser body 11 has a central region 111 and an edge region 112 disposed around the central region 111. Along the thickness direction of the diffusion layer 1, the covering member 12 covers at least one edge region 112 of the diffuser body 11. That is, along the thickness direction of the diffusion layer 1, the diffuser body 11 has a first surface and a second surface. The covering member 12 can cover the edge region 112 of the first surface, the second surface, or both the first and second surfaces.
[0058] It should be noted that in some embodiments, when the covering member 12 covers an edge region 112 on one side of the diffusion body 11 along the thickness direction of the diffusion layer 1, the covering member 12 is used to contact the proton exchange membrane. That is, when the edge region 112 of the first surface (or second surface) of the diffusion body 11 is provided with a recessed portion 112a, the covering member 12 is disposed only within the recessed portion 112a of the first surface (or second surface). When assembling the diffusion layer 1 and the proton exchange membrane, the first surface (or second surface) of the diffusion layer 1 must be in contact with the proton exchange membrane so that the covering member 12 can cover the edge region 112 in contact with the proton exchange membrane, thereby preventing the proton exchange membrane from being penetrated by burrs or cuts in the edge region 112 of the diffusion layer 1.
[0059] like Figure 2 and Figure 3 The figure shows a schematic diagram of the diffusion body 11. To prevent the cover 12 from interfering with the assembly of the membrane electrode assembly, a recess 112a is provided in the edge region 112 of at least one side of the diffusion body 11 along the thickness direction of the diffusion layer 1. The cover 12 is located in the recess 112a. Specifically, Figure 2As shown, along the thickness direction of the diffusion layer 1, the edge area 112 on one side of the diffusion body 11 is provided with a recessed portion 112a. Figure 3 The illustration shows recessed portions 112a provided on the edge regions 112 of the diffuser body 11 on both sides of the diffuser layer 1 along the thickness direction. Specifically, when the recessed portions 112a are provided on the edge regions 112 of the first and / or second surfaces of the diffuser body 11, the cover 12 is positioned within the recessed portions 112a of the first and / or second surfaces to prevent the cover 12 from protruding from the diffuser layer 1 along the thickness direction, thereby interfering with the diffuser layer 1 and affecting subsequent assembly.
[0060] In this embodiment, a covering 12 is provided in the edge area 112 of the diffusion layer 1 (titanium felt) to cover or wrap the sharp edge of the diffusion layer 1, thereby avoiding perforation of the proton membrane due to cuts or burrs on the edge of the diffusion layer 1, thereby avoiding leakage problems and effectively improving the safety of the hydrogen production device.
[0061] like Figure 4 and Figure 5 is a schematic cross-sectional view of the diffusion layer 1. Along the thickness direction of the diffusion layer 1, the surface of the covering member 12 is flush with the surface of the middle region 111. Specifically, Figure 4 The figure shows a cover 12 disposed on one side of the diffuser layer 1. When the first surface of the diffuser body 11 is provided with a recessed portion 112a, the cover 12 is disposed in the recessed portion 112a. On the first surface, the surface of the cover 12 is flush with the surface of the middle region 111. When the second surface of the diffuser body 11 is provided with a recessed portion 112a, the cover 12 is disposed in the recessed portion 112a. On the second surface, the cover 12 is flush with the surface of the middle region 111. Figure 5 The illustration shows a covering 12 disposed on both sides of the diffusion layer 1. When recessed portions 112a are provided on both the first and second surfaces of the diffusion body 11, the covering 12 is disposed in the recessed portions 112a. The surfaces of the covering 12 on the first and second surfaces are flush with the surfaces of the corresponding intermediate regions 111. This embodiment ensures close contact between the proton exchange membrane and the diffusion layer 1 while preventing interference with the assembly of the membrane electrode assembly.
[0062] In some embodiments, the outer edge of the covering member 12 is aligned with the outer edge of the recessed portion 112a in a direction perpendicular to the thickness direction of the diffusion layer 1. Figure 4When the covering member 12 is provided on one side of the diffusion body 11 along the thickness direction of the diffusion layer 1, the covering member 12 completely covers the edge region 112 of the diffusion body 11, thereby preventing burrs or cuts in the edge region 112 from penetrating the proton exchange membrane. Alternatively, when the covering member 12 is provided on both sides of the diffusion body 11 along the thickness direction of the diffusion layer 1, the covering member 12 completely covers the edge region 112 of the diffusion body 11, thereby preventing burrs or cuts in the edge region 112 from penetrating the proton exchange membrane.
[0063] Please continue to refer to Figure 5 In some embodiments, the outer edge of the covering member 12 extends beyond the outer edge of the recessed portion 112a in a direction perpendicular to the thickness direction of the diffusion layer 1. Figure 5 When the covering member 12 is provided on both sides of the diffusion body 11 along the thickness direction of the diffusion layer 1, the covering member 12 can extend to cover the side wall of the diffusion body 11 (the side perpendicular to the first and second surfaces) to cover burrs and cuts on the side wall, thereby preventing the burrs and cuts in that area from penetrating the proton exchange membrane. Alternatively, when the covering member 12 is provided on one side of the diffusion body 11 along the thickness direction of the diffusion layer 1, the covering member 12 can also extend to cover the side wall of the diffusion body 11 (the side perpendicular to the first and second surfaces) to cover burrs and cuts on the side wall, thereby preventing the burrs and cuts in that area from penetrating the proton exchange membrane.
[0064] like Figure 6 and Figure 7 The figure shows a schematic diagram of the diffusion body 11 forming a recessed portion 112a. The diffusion body 11 can be made of titanium felt, which is a material with a certain degree of compressibility. The edge area 112 of the diffusion body 11 is formed into the recessed portion 112a by rolling. Figure 6 The edge region 112 of the diffuser body 11 is rolled by the roller 2 on one side, so that a recessed portion 112 a is formed in the edge region 112 on one side of the diffuser body 11 . Figure 7 The edge region 112 of the diffuser body 11 is rolled by the roller 2 on both sides, so that the edge regions 112 on both sides of the diffuser body 11 form recessed portions 112 a.
[0065] 8 is a schematic diagram of the injection mold 3 for injection molding the covering part 12 in the recessed portion 112a. Figure 9 and Figure 10 The figure shows a cross-sectional view of a mold for injection molding the covering member 12 in the recessed portion 112 a . The covering member 12 can be injection molded in the recessed portion 112 a .
[0066] Please refer to the reference for details Figure 8 and Figure 9A recessed portion 112a is provided in the edge region 112 on one side of the diffuser body 11. The injection mold 3 comprises an upper mold and a lower mold, which form a cavity. A glue injection port 31 is provided on one side of the injection mold 3. The diffuser body 11, with the recessed portion 112a provided on one side, is placed in the cavity of the injection mold 3. The glue injection port 31 is positioned corresponding to the recessed portion 112a. The injection material flows through the glue injection port 31 into the recessed portion 112a to form the covering 12.
[0067] Please refer to Figure 8 and Figure 10 The edge regions 112 on both sides of the diffuser body 11 are provided with recessed portions 112a. The injection mold 3 comprises an upper mold and a lower mold, which oppose each other to form a cavity. A glue injection port 31 is provided on the beam side of the injection mold 3. The diffuser body 11, with the recessed portions 112a on both sides, is placed in the cavity of the injection mold 3. The glue injection port 31 is positioned corresponding to the recessed portions 112a. The injection material flows through the glue injection port 31 into the recessed portions 112a to form the cover 12.
[0068] Prior to injection molding, an adhesive may be applied to the recessed portion 112a to enhance the stability of the connection between the cover 12 and the recessed portion 112a after molding. Specifically, the adhesive may be selected from a silane coupling agent, Chemlock, epoxy resin, or other adhesives. Alternatively, other adhesives may be used, and this embodiment is not limited thereto.
[0069] In some embodiments, the material of the covering 12 is selected from plastic or rubber, which has a smooth surface and is acid-resistant and heat-resistant, so that the surface of the covering 12 is smooth and the risk of corrosion of the covering 12 during operation (the general working environment is an acidic environment with a temperature of about 70° and a pH of 2-3) is reduced. This can effectively avoid the problem of puncture of the proton exchange membrane by the edge of the diffusion layer 1, thereby avoiding problems such as leakage, and improving the safety of the operation of the hydrogen production device.
[0070] For example, the material of the covering member 12 can be acid-resistant and heat-resistant plastics such as polyphenylene sulfide and polyetherimide, or the material of the covering member 12 can also be acid-resistant and heat-resistant rubbers such as EPDM and fluororubber. Alternatively, the covering member 12 can also be made of other materials, which are not limited in this embodiment.
[0071] In some embodiments, along the thickness direction of the diffusion layer 1, the thickness of the edge region 112 is 85% to 98% of the thickness of the middle region 111. For example, the thickness of the edge region 112 may be 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, etc., of the thickness of the middle region 111 (the thickness of the original diffusion body 11).
[0072] Correspondingly, along the thickness direction of the diffusion layer 1, the thickness of the covering member 12 is 15% to 2% of the thickness of the middle region 111 (the thickness of the original diffusion body 11). Exemplarily, the thickness of the covering member 12 is 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, or 2% of the thickness of the middle region 111.
[0073] In this embodiment, the ratio of the thickness of the edge region 112 to the thickness of the middle region 111 should be neither too large nor too small. If the ratio is too small (e.g., less than 85%), since the diffusion layer 1 is made of titanium felt, which has low compressibility, it is not possible to roll out a deep recess 112a. If the ratio is too large (e.g., greater than 98%), the depth of the recess 112a is too shallow, and when the recess 112a is injection-molded to form the cover 12, the thickness of the cover 12 is too thin, which can easily lead to molding defects of the cover 12, and the burrs and cuts in the edge region 112 cannot be completely covered, and there is still a risk of puncturing the proton exchange membrane.
[0074] In some embodiments, along the thickness direction of the diffusion layer 1, the area of the covering member 12 accounts for 2% to 5% of the area of the diffusion layer 1, i.e., the covering member 12 covers 2% to 5% of the surface area of one side of the diffusion layer 1. For example, the area of the covering member 12 accounts for 2%, 3%, 4%, or 5% of the area of the diffusion layer 1.
[0075] In this embodiment, the ratio of the area of the covering member 12 to the area of the diffusion layer 1 should be neither too large nor too small. If the ratio is too large (e.g., greater than 5%), the covering member 12 covers a larger area of the diffusion layer 1, affecting the effective contact area of the diffusion layer 1. If the ratio is too small (e.g., less than 2%), the covering member 12 covers a smaller area of the edge region 112 of the diffusion layer 1, which may result in burrs or cuts in the edge region 112 being exposed and piercing the proton exchange membrane.
[0076] Based on the above structural content, the possible formation structure and method of the diffusion layer 1 will be described below.
[0077] In a specific embodiment, please refer to Figure 1 、 Figure 2 、 Figure 4 、 Figure 6 、 Figure 8 and Figure 9In this embodiment, the edge area 112 on one side of the diffusion body 11 is subjected to a rolling process to form a recessed portion 112a, and a covering part 12 is formed by injection molding in the recessed portion 112a. The covering part 12 injected into the recessed portion 112a is made of polyphenylene sulfide. The diffusion body 11 uses titanium felt, which is a compressible material. The edge area 112 of the titanium felt is compressed to 90% of the initial height by unilateral rolling. The edge area 112 after rolling is coated with a silane coupling agent and placed in the injection mold 3. Injection molding is performed through the unilateral injection port 31 of the injection mold 3 to form a layer of covering part 12 in the recessed portion 112a. The thickness of the covering part 12 is 10% of the initial thickness of the titanium felt. After the injection molding is completed, a diffusion layer 1 that prevents the proton exchange membrane from being punctured is obtained. During assembly, the side of the diffusion layer 1 with the covering 12 contacts the proton exchange membrane, and the side without the covering 12 contacts the electrode plate. Since the surface of the polyphenylene sulfide covering 12 is smooth, the edge of the diffusion layer 1 can effectively avoid puncturing the proton exchange membrane, thereby avoiding the resulting leakage.
[0078] In another specific embodiment, please refer to Figure 1 、 Figure 3 、 Figure 5 、 Figure 7 、 Figure 8 and Figure 10 In this embodiment, the edge areas 112 on both sides of the diffusion body 11 are rolled to form a recessed portion 112a, and a covering part 12 is formed by injection molding in the recessed portion 112a. The covering part 12 injected into the recessed portion 112a is made of EPDM rubber. The diffusion body 11 is made of titanium felt, which is a compressible material. The edge area 112 of the titanium felt is compressed to 88% of the initial height by double-sided rolling. The edge area 112 after rolling is coated with epoxy resin and placed in the injection mold 3. Injection molding is performed through the double-sided glue injection ports 31 of the injection mold 3 to form a layer of covering part 12 in the recessed portion 112a. The thickness of the covering part 12 is 12% of the initial thickness of the titanium felt. After the injection molding is completed, a diffusion layer 1 that prevents the proton exchange membrane from being punctured is obtained. During assembly, the side of the diffusion layer 1 with the covering 12 contacts the proton exchange membrane. Since the surface of the EPDM covering 12 is smooth, the edge of the diffusion layer 1 can be effectively prevented from puncturing the proton exchange membrane, thereby avoiding the resulting leakage.
[0079] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.
Claims
1. A diffusion layer, characterized in that: The diffusion layer (1) comprises: A diffusion body (11), the diffusion body (11) having a middle region (111) and an edge region (112) arranged on the periphery of the middle region (111); a covering member (12), wherein along the thickness direction of the diffusion layer (1), the covering member (12) covers at least the edge region (112) on one side of the diffusion body (11); The edge region (112) on at least one side of the diffusion body (11) is provided with a recessed portion (112a), and the covering component (12) is provided in the recessed portion (112a).
2. The diffusion layer according to claim 1, characterized in that Along the thickness direction of the diffusion layer (1), the surface of the covering member (12) is flush with the surface of the middle region (111).
3. The diffusion layer according to claim 1, characterized in that Along the thickness direction of the diffusion layer (1), the thickness of the edge region (112) is 85% to 98% of the thickness of the middle region (111).
4. The diffusion layer according to claim 1, characterized in that Along a direction perpendicular to the thickness direction of the diffusion layer (1), the outer edge of the covering member (12) is aligned with the outer edge of the recessed portion (112a); or, Along a direction perpendicular to the thickness direction of the diffusion layer (1), the outer edge of the covering member (12) extends beyond the outer edge of the recessed portion (112a).
5. The diffusion layer according to any one of claims 1 to 4, characterized in that: When the covering member (12) covers the edge region (112) on one side of the diffusion body (11) along the thickness direction of the diffusion layer (1), the covering member (12) is used to contact the proton exchange membrane.
6. The diffusion layer according to any one of claims 1 to 4, characterized in that The diffusion body (11) is titanium felt, and the edge area (112) is formed into the recessed portion (112a) by rolling.
7. The diffusion layer according to any one of claims 1 to 4, characterized in that: The covering piece (12) is injection-molded in the recessed portion (112a).
8. The diffusion layer according to any one of claims 1 to 4, characterized in that: The material of the covering member (12) is one of polyphenylene sulfide, polyetherimide, EPDM rubber and fluororubber.
9. A membrane electrode assembly, characterized in that: The membrane electrode assembly comprises: Proton exchange membrane; A diffusion layer (1), wherein the diffusion layer (1) is the diffusion layer (1) according to any one of claims 1 to 8, and the diffusion layer (1) is provided with a coating (12) on one side thereof in contact with the proton exchange membrane.
10. A hydrogen production device, characterized in that: The hydrogen production device comprises: Plates; A membrane electrode assembly, wherein the electrode plate and the membrane electrode assembly are stacked, and the membrane electrode assembly is the membrane electrode assembly according to claim 9.