Membrane electrode assembly, PEM electrolytic bath and assembling method

Abstract

The invention discloses a membrane electrode assembly, a PEM electrolytic bath and an assembling method, the membrane electrode assembly comprises a proton membrane, an anode diffusion layer, a cathode diffusion layer and an outer frame, the peripheral size of the anode diffusion layer is the same as that of the proton membrane, and the anode diffusion layer is bonded to the anode side of the proton membrane; the peripheral size of the cathode diffusion layer is smaller than that of the proton membrane, and the cathode diffusion layer is adhered to the middle position of the cathode side of the proton membrane; the outer frame is provided with an inner frame body and an outer frame body, the inner frame body is arranged along the periphery of the cathode diffusion layer, the surface of one side of the inner frame body is bonded with the cathode side of the proton membrane, and the outer frame body extends outwards to the outer side of the proton membrane. The anode diffusion layer, the proton membrane, the cathode diffusion layer and the outer frame are bonded into a whole, the complexity of follow-up assembly is reduced, the dislocation risk is reduced, the shearing risk of the proton membrane is reduced, the proton membrane is supported through the high strength of the anode diffusion layer, the strength of the proton membrane is improved, and the proton membrane swells in a dry and wet mode and is not prone to deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PEM electrolytic water hydrogen production, in particular to a membrane electrode assembly, a PEM electrolytic tank and an assembling method. BACKGROUND

[0002] In the PEM electrolytic tank device, the membrane electrode and the bipolar plate are alternately stacked. The membrane electrode assembly mainly includes a proton membrane, an anode and a cathode catalyst, an anode and a cathode diffusion layer, etc. Due to the large active area of the PEM electrolytic water membrane electrode, the thick proton membrane is easy to deform, and the high thickness and heavy quality of the anode and cathode gas diffusion layers, etc., the anode and cathode diffusion layers are assembled separately from the proton membrane in the traditional electrolytic water membrane electrode assembly. This assembly method increases the complexity of assembly and increases the risk of misalignment, and the edge of the diffusion layer is easy to pierce the proton membrane during the stacking and fastening process. SUMMARY The present application aims to provide a membrane electrode assembly, a PEM electrolytic tank and an assembling method to solve one or more technical problems existing in the prior art, at least to provide a beneficial choice or create conditions.

[0003] To solve the above technical problems, the technical scheme adopted by the present application is: The present application provides a membrane electrode assembly, comprising: a proton membrane; an anode diffusion layer, the outer peripheral size of which is the same as that of the proton membrane, the anode diffusion layer being bonded to the anode side of the proton membrane; a cathode diffusion layer, the outer peripheral size of which is smaller than that of the proton membrane, the cathode diffusion layer being bonded to the middle position of the cathode side of the proton membrane; an outer frame, provided with an inner frame body and an outer frame body, the inner frame body being arranged along the four sides of the cathode diffusion layer, one side surface of the inner frame body being bonded to the cathode side of the proton membrane, and the outer frame body extending outwardly to the outside of the proton membrane.

[0004] The membrane electrode assembly of the present application has the following beneficial effects: The anode diffusion layer, the proton membrane, the cathode diffusion layer and the outer frame are bonded together in the present application, reducing the complexity of subsequent assembly and reducing the risk of misalignment, thereby reducing the risk of proton membrane shearing. In addition, the outer peripheral size of the anode diffusion layer and the proton membrane is set to be the same, which can rely on the high strength of the anode diffusion layer to support the proton membrane, increase the strength of the proton membrane, and make it difficult for the proton membrane to swell and deform. The present application can effectively handle the relationship between the edge of the diffusion layer and the proton membrane, thereby avoiding piercing the proton membrane.

[0005] As a further improvement of the above technical scheme, the four sides of the anode side of the proton membrane are bonded to the four sides of the anode diffusion layer; The proton membrane cathode side is bonded with the four sides of the cathode diffusion layer and the four sides of the inner frame body respectively.

[0006] As a further improvement of the above technical solution, the proton membrane, the anode diffusion layer, the cathode diffusion layer and the outer frame are bonded by direct hot pressing.

[0007] As a further improvement of the above technical solution, the proton membrane, the anode diffusion layer, the cathode diffusion layer and the outer frame are bonded by direct hot pressing.

[0008] As a further improvement of the above technical solution, the membrane electrode assembly further comprises two point gluing frames, two point gluing frames are attached to the cathode side and the anode side of the proton membrane respectively, and the point gluing frame is arranged along the four sides of the proton membrane, the four sides of the proton membrane are connected to the four sides of the anode diffusion layer through the point gluing frame on the anode side, and the four sides of the proton membrane are connected to the four sides of the outer frame and the four sides of the cathode diffusion layer through the point gluing frame on the cathode side.

[0009] As a further improvement of the above technical solution, the membrane electrode assembly further comprises two microporous layers, one of which is arranged on the anode side of the proton membrane and in the inner frame of the point gluing frame on the anode side, and the other is arranged on the cathode side of the proton membrane and in the inner frame of the point gluing frame on the cathode side.

[0010] As a further improvement of the above technical solution, the point gluing frame is one or more of hot melt glue, pressure sensitive adhesive and UV glue.

[0011] As a further improvement of the above technical solution, the two side surfaces of the proton membrane are respectively coated with a cathode catalyst and an anode catalyst.

[0012] The present application provides a PEM electrolytic cell, comprising a plurality of the membrane electrode assemblies, and further comprising a plurality of bipolar plates stacked in sequence, the membrane electrode assembly is clamped between two adjacent bipolar plates, and the outer frame body extends to the edge of the bipolar plate.

[0013] The present application further provides an assembly method of a PEM electrolytic cell, which is suitable for the PEM electrolytic cell, and the assembly method comprises: controlling the anode side of the proton membrane to be bonded with the anode diffusion layer by hot pressing under first preset hot pressing conditions; controlling the cathode side of the proton membrane to be bonded with the cathode diffusion layer by hot pressing under second preset hot pressing conditions; controlling the cathode side of the proton membrane to be bonded with the outer frame by hot pressing under third preset hot pressing conditions, so as to form the membrane electrode assembly. The hot-pressed membrane electrode assembly is sequentially placed between two adjacent bipolar plates according to a preset stacking number; The stacked bipolar plate and the membrane electrode assembly are fastened and pressed according to a preset fastening and pressing condition.

[0014] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0015] The present application will be further described below in conjunction with the accompanying drawings and examples; Figure 1 is an assembly exploded view of a membrane electrode assembly provided by the present application, an embodiment of which adopts a point-gluing hot-pressing bonding mode; Figure 2 is an assembly view of a PEM electrolytic cell provided by the present application, an embodiment of the membrane electrode assembly of which adopts a point-gluing hot-pressing bonding mode; Figure 3 is an assembly exploded view of a membrane electrode assembly provided by the present application, an embodiment of which adopts a direct hot-pressing bonding mode; Figure 4 is an assembly view of a PEM electrolytic cell provided by the present application, an embodiment of the membrane electrode assembly of which adopts a direct hot-pressing bonding mode; Figure 5 is a flow chart of an assembly method of a PEM electrolytic cell provided by the present application, an embodiment of which is shown; REFERENCE NUMERALS Proton membrane 100; Anode diffusion layer 200; Cathode diffusion layer 300; Outer frame 400; inner frame body 410; outer frame body 420; Point-gluing frame 500; Microporous layer 600; Bipolar plate 700. DETAILED DESCRIPTION

[0016] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary only, and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0017] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, etc., is based on the orientation or position relationship shown in the drawings, only for the purpose of facilitating the description of the present application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0018] In the description of the present application, more refers to more than two. If there is a description of first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0019] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0020] The technical solutions of the present application will be described below in conjunction with the drawings. Obviously, the following described embodiments are part of the embodiments of the present application, not all embodiments.

[0021] In the PEM electrolyzer device, the membrane electrode and the bipolar plate 700 are alternately stacked. The membrane electrode assembly mainly includes a proton membrane 100, a cathode and anode catalyst, a cathode and anode diffusion layer 200, etc. Due to the factors such as large active area of the PEM electrolysis water membrane electrode, thick proton membrane 100 prone to deformation, and high thickness and heavy quality of the cathode and anode gas diffusion layer, the cathode and anode diffusion layer 200 and the proton membrane 100 are assembled separately in the traditional electrolysis water membrane electrode assembly. This assembly method increases the complexity of assembly and also increases the risk of misalignment, and the diffusion layer edge is prone to pierce the proton membrane 100 during the stacking and fastening process.

[0022] For the above assembly risk, some membrane electrode structure design patents have been found and improved, such as the patent CN117210838A, which assembles the cathode and anode diffusion layer 200 and the proton membrane 100 together through hot pressing, increasing the convenience of assembly. However, it does not pay attention to the edge state of the cathode and anode diffusion layer 200, resulting in the risk of the proton membrane 100 being pierced by the cathode and anode diffusion layer 200 during hot pressing. In addition, the cathode and anode diffusion layer 200 has the same size, and misalignment will inevitably occur during hot pressing, thereby shearing the proton membrane 100 and causing great damage to the durability of the proton membrane 100.

[0023] Therefore, the present application is designed to reduce the risk of shearing the proton membrane 100 and increase the convenience of assembling the electrolyzer, and a membrane electrode assembly, a PEM electrolyzer and an assembly method are designed.

[0024] Reference Figures 1-4 The membrane electrode assembly of the present invention is provided in the following embodiments: like Figure 1 As shown, the membrane electrode assembly of the present invention includes: a proton membrane 100, an anode diffusion layer 200, a cathode diffusion layer 300, and an outer frame 400.

[0025] The anode diffusion layer 200 is made of titanium felt or other corrosion-resistant fibers. In this embodiment, 0.8 mm sintered titanium is selected.

[0026] The cathode diffusion layer 300 is made of titanium felt, titanium felt or other inexpensive metal fibers plated with titanium, gold, platinum, etc. In this embodiment, a 1mm carbon fiber gas diffusion layer is selected.

[0027] like Figure 1 and Figure 2 As shown, the outer periphery of the anode diffusion layer 200 is the same as that of the proton exchange membrane 100, and the anode diffusion layer 200 is bonded to the anode side of the proton exchange membrane 100. The outer periphery of the cathode diffusion layer 300 is smaller than that of the proton exchange membrane 100, and the cathode diffusion layer 300 is bonded to the middle position on the cathode side of the proton exchange membrane 100.

[0028] The outer frame 400 of the present invention is provided with an inner frame 410 and an outer frame 420 disposed inside and outside. The inner frame 410 is disposed around the cathode diffusion layer 300. One side surface of the inner frame 410 is bonded to the cathode side of the proton exchange membrane 100. The outer frame 420 extends outward to the outer side of the proton exchange membrane 100.

[0029] This invention integrates the anode diffusion layer 200, proton exchange membrane 100, cathode diffusion layer 300, and outer frame 400 into a single unit, reducing the complexity of subsequent assembly and minimizing the risk of misalignment, thereby reducing the risk of shearing of the proton exchange membrane 100. Furthermore, by setting the outer periphery dimensions of the anode diffusion layer 200 and the proton exchange membrane 100 to be identical, the high strength of the anode diffusion layer 200 can support the proton exchange membrane 100, increasing the strength of the proton exchange membrane 100 and making it less prone to deformation due to wet and dry swelling. This invention can effectively handle the relationship between the edge of the diffusion layer and the proton exchange membrane 100, thereby avoiding damage to the proton exchange membrane 100.

[0030] Furthermore, such as Figure 1 and Figure 2 As shown, the periphery of the anode side of the proton exchange membrane 100 is bonded to the periphery of the anode diffusion layer 200, and the periphery of the cathode side of the proton exchange membrane 100 is bonded to the periphery of the cathode diffusion layer 300 and the periphery of the inner frame 410, respectively. It can be understood that the periphery of the cathode diffusion layer 300 and the anode diffusion layer 200 are inactive regions, and the region in the middle is the active region. In this embodiment, the cathode diffusion layer 300 and the anode diffusion layer 200 are bonded to the proton exchange membrane 100 through the inactive regions.

[0031] In some embodiments, such as Figure 3 and Figure 4 As shown, the proton exchange membrane 100, the anode diffusion layer 200, the cathode diffusion layer 300, and the outer frame 400 are bonded together by direct hot pressing.

[0032] In this embodiment, the proton exchange membrane 100, the anode diffusion layer 200, the cathode diffusion layer 300, and the outer frame 400 are bonded together by dispensing and hot pressing. The adhesive can be one or more of hot melt adhesive, pressure-sensitive adhesive, and UV adhesive.

[0033] When applying adhesive and hot-press bonding between the cathode diffusion layer 300, the anode diffusion layer 200, and the proton exchange membrane 100, the adhesive should not be applied directly to the proton exchange membrane 100. Figure 1 and Figure 2 As shown, the membrane electrode assembly of this embodiment also includes two adhesive-coated frames 500. The two adhesive-coated frames 500 are respectively attached to the cathode side and the anode side of the proton exchange membrane 100, and the adhesive-coated frames 500 are arranged around the periphery of the proton exchange membrane 100. The periphery of the proton exchange membrane 100 is connected to the periphery of the anode diffusion layer 200 by adhesive-coated frame 500 on the anode side, and the periphery of the proton exchange membrane 100 is connected to the periphery of the outer frame 400 and the periphery of the cathode diffusion layer 300 by adhesive-coated frame 500 on the cathode side.

[0034] Understandably, during assembly, adhesive-coated borders 500 need to be attached to both sides of the proton exchange membrane 100 first, with the adhesive application point at the adhesive-coated border 500. The anodic diffusion layer 200 is then aligned and bonded to the proton exchange membrane 100 by hot pressing, and then aligned and bonded to the anion diffusion layer by hot pressing.

[0035] The thickness of the adhesive border 500 should be <100um, and the thickness of the outer border 400 should be >120um. In this embodiment, the outer border 400 is 150um and the adhesive border 500 is 30um.

[0036] During the hot pressing process of dispensing adhesive, the thickness of the dispensing border 500 causes a hollow area to appear in the middle region of the dispensing border 500, such as... Figure 1 and Figure 2 As shown, the membrane electrode assembly of this embodiment also includes two microporous layers 600. One microporous layer 600 is disposed on the anode side of the proton exchange membrane 100 and is located in the inner frame of the dispensing frame 500 on the anode side. The other microporous layer 600 is disposed on the cathode side of the proton exchange membrane 100 and is located in the inner frame of the dispensing frame 500 on the cathode side. The microporous layer 600 compensates for the support thickness of the dispensing frame 500, thereby ensuring good electrical contact of the active area.

[0037] In this embodiment, the two sides of the proton exchange membrane 100 are coated with a cathode catalyst and an anode catalyst, respectively. Before the adhesive hot-press bonding, the cathode catalyst and the anode catalyst are coated on the two sides of the proton exchange membrane 100, and then the adhesive frame 500 is attached.

[0038] like Figure 2 and Figure 4 As shown, the present invention proposes a PEM electrolyzer, which includes multiple membrane electrode assemblies and multiple bipolar plates 700 stacked in sequence. The membrane electrode assemblies are sandwiched between two adjacent bipolar plates 700. The outer frame 420 extends to the edges of the bipolar plates 700 in all directions, mainly serving to insulate and position the membrane electrodes.

[0039] This invention also proposes an assembly method for a PEM electrolyzer, applicable to the aforementioned PEM electrolyzer, such as... Figure 5 As shown, the assembly method includes: Step S100: The anode side of the proton exchange membrane 100 and the anode diffusion layer 200 are aligned and hot-pressed together according to the first preset hot-pressing conditions. Step S200: The cathode side of the proton exchange membrane 100 and the cathode diffusion layer 300 are aligned and hot-pressed together according to the second preset hot-pressing conditions. Step S300: The cathode side of the proton exchange membrane 100 is aligned and hot-pressed with the outer frame 400 according to the third preset hot-pressing conditions to form a membrane electrode assembly. Step S400: Place the hot-pressed membrane electrode assembly between two adjacent bipolar plates 700 according to the preset stacking quantity; Step S500: Fasten and press the stacked bipolar plate 700 and membrane electrode assembly according to the preset fastening and pressing conditions.

[0040] In step S100, if the dispensing and hot pressing method is used, such as Figure 1 and Figure 2 As shown, the cathode catalyst and the anode catalyst are pre-coated on both sides of the proton exchange membrane 100, and then the adhesive frame 500 on the anode side is attached. A microporous layer 600 is coated on the active area of ​​the anode diffusion layer 200, and adhesive is applied to the adhesive frame 500. The first preset hot pressing conditions are: temperature 120-140℃, pressure 1-3MPa, and time 3min.

[0041] If direct hot pressing is used, such as Figure 3 and Figure 4 As shown, remove the glued border 500.

[0042] In step S200, if the dispensing hot pressing method is used, the dispensing frame 500 on the cathode side is attached, the dispensing frame 500 is dispensed, and the microporous layer 600 is coated in the active area of ​​the cathode diffusion layer 300. The second preset hot pressing conditions are: temperature 120-140℃, pressure 0.5-2MPa, time 3min.

[0043] In some other embodiments, the cathode diffusion layer 300, the anode diffusion layer 200, and the proton exchange membrane 100 are simultaneously aligned and hot-pressed.

[0044] In step S300, the third preset hot pressing condition is similar to the second preset hot pressing condition and the first preset hot pressing condition.

[0045] In step S400, when placing the membrane electrode assembly, the sealing ring is attached to both sides of the outer frame 400.

[0046] In step S500, the bipolar plate 700 is pressed according to a preset pressure and the pressure is maintained for a preset time.

[0047] The present invention allows the membrane electrode assembly to be press-fitted first, and then assembled and fastened with the bipolar plate 700, which reduces the risk of shearing of the proton exchange membrane 100 and increases the ease of assembly of the electrolyzer.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A membrane electrode assembly, characterized in that, include: Proton membrane; An anode diffusion layer having the same outer circumferential dimensions as the proton exchange membrane, the anode diffusion layer being bonded to the anode side of the proton exchange membrane; A cathode diffusion layer having an outer perimeter smaller than the proton exchange membrane, the cathode diffusion layer being bonded to the middle position on the cathode side of the proton exchange membrane; The outer frame has an inner frame and an outer frame. The inner frame is arranged around the cathode diffusion layer. One side surface of the inner frame is bonded to the cathode side of the proton membrane. The outer frame extends outward to the outside of the proton membrane.

2. The membrane electrode assembly according to claim 1, characterized in that: The periphery of the proton exchange membrane on the anode side is bonded to the periphery of the anode diffusion layer; The periphery of the proton membrane cathode side is bonded to the periphery of the cathode diffusion layer and the periphery of the inner frame, respectively.

3. The membrane electrode assembly according to claim 2, characterized in that: The proton exchange membrane, the anode diffusion layer, the cathode diffusion layer, and the outer frame are bonded together by direct hot pressing.

4. The membrane electrode assembly according to claim 2, characterized in that: The proton exchange membrane, the anode diffusion layer, the cathode diffusion layer, and the outer frame are bonded together by dispensing and hot pressing.

5. The membrane electrode assembly according to claim 4, characterized in that: The membrane electrode assembly further includes two adhesive-coated frames, which are respectively attached to the cathode side and the anode side of the proton exchange membrane. The adhesive-coated frames are arranged around the perimeter of the proton exchange membrane. The perimeter of the proton exchange membrane is connected to the perimeter of the anode diffusion layer by adhesive-coated frame on the anode side, and the perimeter of the proton exchange membrane is connected to the outer frame and the perimeter of the cathode diffusion layer by adhesive-coated frame on the cathode side.

6. The membrane electrode assembly according to claim 5, characterized in that: The membrane electrode assembly further includes two microporous layers, one of which is disposed on the anode side of the proton membrane and located within the inner frame of the dispensing frame on the anode side, and the other microporous layer is disposed on the cathode side of the proton membrane and located within the inner frame of the dispensing frame on the cathode side.

7. The membrane electrode assembly according to claim 5, characterized in that: The adhesive used for the adhesive-coated border is one or more of hot melt adhesive, pressure-sensitive adhesive, and UV adhesive.

8. The membrane electrode assembly according to claim 5, characterized in that: The two sides of the proton exchange membrane are coated with a cathode catalyst and an anode catalyst, respectively.

9. A PEM electrolytic cell, characterized in that: The device includes multiple membrane electrode assemblies as described in any one of claims 1 to 8, and further includes multiple bipolar plates stacked sequentially, wherein the membrane electrode assembly is sandwiched between two adjacent bipolar plates, and the outer frame extends outward to the edges of the bipolar plates.

10. A method for assembling a PEM electrolytic cell, characterized in that, The assembly method, applicable to the PEM electrolyzer as described in claim 9, comprises: The anode side of the proton membrane is aligned and hot-pressed with the anode diffusion layer according to the first preset hot-pressing conditions. The cathode side of the proton membrane is aligned and hot-pressed with the cathode diffusion layer according to the second preset hot-pressing conditions. The cathode side of the proton exchange membrane is aligned and hot-pressed with the outer frame according to the third preset hot-pressing conditions to form the membrane electrode assembly. The hot-pressed membrane electrode assembly is placed sequentially between two adjacent bipolar plates according to the preset stacking quantity; The stacked bipolar plates and the membrane electrode assembly are fastened and pressed together according to the preset fastening and pressing conditions.

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