Membrane electrode assembly, cell, and stack

Abstract

The utility model relates to the technical field of membrane electrode, especially to a kind of membrane electrode assembly, battery unit and electric pile.The membrane electrode assembly includes: membrane electrode layer, membrane electrode layer includes proton membrane layer;And two frame film layers, membrane electrode layer is set between two frame film layers, the middle part of frame film layer is equipped with the opening hole corresponding with catalyst layer, frame film layer has uniform thickness, at least one frame film layer includes multiple spliced layers that mutually bond and splice, the thickness of frame film layer including multiple spliced layers is greater than the thickness of spliced layer, and at least the cathode surface of proton membrane layer is set frame film including multiple spliced layers.In the utility model, the thickness of at least one frame film layer increases, and its structural strength is also further increased, so that the deformation of frame film layer in electric pile pressing process can be prevented, thereby avoiding the support and protection intensity of membrane electrode layer to reduce.

Description

Technical Field

[0001] This utility model relates to the field of membrane electrode technology, and in particular to a membrane electrode assembly, a battery cell, and a battery stack. Background Technology

[0002] The membrane electrode assembly (MEA) is one of the core components of a fuel cell stack, serving as the site of electrochemical reactions. The MEA consists of a membrane electrode layer, with frame membrane layers on both sides. These frame membrane layers act as pads on the surface of the membrane electrode layer, providing support and protection to prevent damage during the stack assembly process.

[0003] The border film is obtained by cutting the membrane material, so its thickness is the same as that of the membrane material layer. However, the border film is relatively thin, making it prone to deformation during the stacking process, which reduces its support and protection for the membrane electrode layer. Utility Model Content

[0004] One of the technical problems that this utility model aims to solve is that the thickness of the frame film layer is relatively thin, and the frame film layer is easily deformed during the stacking process, which reduces the support and protection of the membrane electrode layer.

[0005] To address the aforementioned technical problems, this utility model provides a membrane electrode assembly, comprising: a membrane electrode layer including a proton exchange membrane layer, a catalyst layer disposed at the center of both sides of the proton exchange membrane layer, and a carbon paper layer disposed on the side of the catalyst layer opposite to the proton exchange membrane layer, the carbon paper layer completely covering the corresponding catalyst layer; and two frame membrane layers, the membrane electrode layer disposed between the two frame membrane layers, the frame membrane layers having openings corresponding to the catalyst layers at their center, the frame membrane layers being distributed around the catalyst layers, the periphery of the carbon paper layer being attached to the corresponding frame membrane layer, and the periphery of the proton exchange membrane layer being attached to the frame membrane layer; wherein, the frame membrane layers have a uniform thickness, at least one frame membrane layer includes multiple splicing layers that are bonded together, the thickness of the frame membrane layer including multiple splicing layers is greater than the thickness of the splicing layers, and at least the cathode surface of the proton exchange membrane layer is provided with a frame membrane including multiple splicing layers.

[0006] In some embodiments, the border film layer includes two end film layers spaced apart along its length direction and two side film layers spaced apart along its width direction, with all end film layers and all side film layers surrounding the opening.

[0007] In some embodiments, the two border film layers are a first border film layer and a second border film layer, respectively. The first border film layer is disposed on the anode surface of the proton exchange membrane layer, and the thickness of the first border film layer is equal to the thickness of the splicing layer. The first border film layer is integrally formed. The second border film layer is disposed on the cathode surface of the proton exchange membrane layer, and the second border film layer includes multiple splicing layers that are bonded together with each other. The thickness of the second border film layer is at least twice the thickness of the splicing layer.

[0008] In some embodiments, the multiple splicing layers include multiple first splicing layers and multiple second splicing layers; the side film layer of the second border film layer includes a first outer layer portion, a middle layer portion and a second outer layer portion distributed sequentially along its thickness direction; the first outer layer portion, the middle layer portion and the second outer layer portion each include multiple first splicing layers that are sequentially laid and adjacent to each other along the length direction of the second border film layer, all the first splicing layers of the first outer layer portion are staggered from all the first splicing layers of the middle layer portion, and all the first splicing layers of the second outer layer portion are staggered from all the first splicing layers of the middle layer portion.

[0009] In some embodiments, the end film layer of the second border film layer includes three second splicing layers stacked along its thickness direction, the three second splicing layers being adjacent to the first splicing layer of the first outer layer portion, the first splicing layer of the middle layer portion, and the first splicing layer of the second outer layer portion, respectively.

[0010] In some embodiments, one of the middle second splicing layers has two clearance notches, the two clearance notches are spaced apart along the width direction of the second border film layer, and the first splicing layers of the two middle layers extend into the two clearance notches respectively.

[0011] In some embodiments, another second splicing layer located in the middle extends between the first splicing layer of the first outer layer portion and the first splicing layer of the second outer layer portion.

[0012] In some embodiments, the first splicing layer of the middle layer has an elongated hole extending along its length direction, the elongated hole being disposed between the seams of adjacent first splicing layers, and the width of the elongated hole being less than or equal to the thickness of the first splicing layer.

[0013] This utility model also provides a battery unit, which includes two bipolar plates and a membrane electrode assembly as described in the above embodiment, wherein the membrane electrode assembly is disposed between the two bipolar plates.

[0014] This invention also provides a battery stack, which includes a plurality of battery cells described in the above embodiments.

[0015] The above-mentioned technical solution of this utility model has the following technical effects:

[0016] At least one frame membrane layer comprises multiple interlocking layers that are bonded together, and the thickness of the frame membrane layer comprising multiple interlocking layers is greater than the thickness of the interlocking layers. That is, the thickness of the frame membrane layer comprising multiple interlocking layers is greater than the thickness of the membrane material. Therefore, as the thickness of at least one frame membrane layer increases, its structural strength will also increase further. This can prevent the frame membrane layer from deforming during the electrode stack pressing process, thereby avoiding a reduction in the support and protection of the membrane electrode layer. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional schematic diagram of a membrane electrode assembly in one embodiment of the present invention;

[0019] Figure 2 This is a cross-sectional schematic diagram of the membrane electrode layer in one embodiment of the present invention;

[0020] Figure 3 This is a top view of the first frame film in one embodiment of the present invention;

[0021] Figure 4 This is a top view of the second frame film in one embodiment of the present invention;

[0022] Figure 5 yes Figure 4 A schematic diagram of the cross section at point L on the middle line;

[0023] Figure 6 This is a schematic diagram of the splicing of the first outer layer or the second outer layer in one embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the splicing of the middle layer in one embodiment of this utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Membrane electrode layer; 11. Proton exchange membrane layer; 12. Catalyst layer; 13. Carbon paper layer;

[0027] 2. Frame film layer; 21. Opening; 22. First frame film layer; 23. Second frame film layer; 24. End film layer; 25. Side film layer; 251. First outer layer portion; 252. Middle layer portion; 253. Second outer layer portion; 26. Splicing layer; 261. First splicing layer; 262. Second splicing layer; 263. Avoidance notch; 264. Extension portion; 265. Elongated hole. Detailed Implementation

[0028] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to exemplarily illustrate the principles of this utility model, but should not be used to limit the scope of this utility model. This utility model can be implemented in many different forms and is not limited to the specific embodiments of the utility model described herein, but includes all technical solutions falling within the scope of the claims.

[0029] These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0030] It should be noted that, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Furthermore, the terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well.

[0032] It should also be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0033] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this invention pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0035] In existing technologies, traditional border membrane layers are typically cut from a single piece of membrane material, so the thickness of the traditional border membrane layer is equal to the thickness of the membrane material. Furthermore, cutting traditional border membrane layers generates a significant amount of leftover material, which is discarded as waste, resulting in very low utilization of the membrane material. However, membrane materials are expensive, so fully utilizing the leftover material and increasing the utilization rate of the membrane material could significantly reduce production costs.

[0036] like Figures 1 to 4 As shown, this utility model provides a membrane electrode assembly, which includes a membrane electrode layer 1 and two frame membrane layers 2. The membrane electrode layer 1 includes a proton membrane layer 11, and a catalyst layer 12 is provided in the middle of both sides of the proton membrane layer 11. A carbon paper layer 13 is provided on the side of the catalyst layer 12 that is opposite to the proton membrane layer 11, and the carbon paper layer 13 completely covers the corresponding catalyst layer 12. The membrane electrode layer 1 is disposed between two frame membrane layers 2. The frame membrane layer 2 has an opening 21 in the middle corresponding to the catalyst layer 12. The frame membrane layer 2 is distributed around the catalyst layer 12. The periphery of the carbon paper layer 13 is attached to the corresponding frame membrane layer 2. The periphery of the proton membrane layer 11 is attached to the frame membrane layer 2. The frame membrane layer 2 has a uniform thickness. At least one frame membrane layer 2 includes multiple splicing layers 26 that are bonded together. The thickness of the frame membrane layer 2 including multiple splicing layers 26 is greater than the thickness of the splicing layers 26. At least the cathode surface of the proton membrane layer 11 is provided with a frame membrane layer 2 including multiple splicing layers 26.

[0037] Specifically, the proton exchange membrane layer 11 has a proton conduction function; the catalytic layer has a catalytic function, accelerating the redox reaction; the border membrane layer 2 has a supporting function; and the carbon paper layer 13 has a gas diffusion function, transporting water and gas. The border membrane layer 2 can be made of polyethylene naphthalate, polyimide, polyphenylene sulfide, or polypropylene, etc. The two sides of the proton exchange membrane layer 11 are the anode and cathode sides, respectively, and two border membrane layers 2 are respectively disposed on the anode and cathode sides of the proton exchange membrane layer 11. The excess material obtained from cutting the membrane material can be further cut into small splicing layers 26. One border membrane layer 2 can be formed by bonding these small splicing layers 26 together; the other border membrane layer 2 can be cut from the membrane material as a whole, or it can be formed by bonding these small splicing layers 26 together. However, the cathode side of the proton exchange membrane layer 11 is provided with a border membrane layer 2 including multiple splicing layers 26. When one of the frame membrane layers 2 is cut from the membrane material as a whole, the thickness of the frame membrane layer 2 is equal to the thickness of the splicing layer 26. The thickness of the frame membrane layer 2, which includes multiple splicing layers 26, is greater than the thickness of the membrane material.

[0038] In this invention, at least one frame film layer 2 includes multiple splicing layers 26 that are bonded and spliced ​​together. The thickness of the frame film layer 2 including the multiple splicing layers 26 is greater than the thickness of the splicing layers 26. That is, the thickness of the frame film layer 2 including the multiple splicing layers 26 is greater than the thickness of the film material. Therefore, as the thickness of at least one frame film layer 2 increases, its structural strength will also increase further. This can prevent the frame film layer 2 from deforming during the electrode stack pressing process, thereby avoiding a reduction in the support and protection of the membrane electrode layer 1.

[0039] Furthermore, the leftover material obtained from cutting the membrane material is further cut into small splicing layers 26. These small splicing layers 26 are bonded together to form the frame membrane layer 2. Therefore, the leftover material is fully utilized, improving the utilization rate of the membrane material and significantly reducing production costs. Thus, without increasing production costs, this invention can effectively support and protect the membrane electrode layer 1.

[0040] In some embodiments, both frame membrane layers 2 include multiple splicing layers 26 that are bonded together with each other, and these two frame membrane layers 2 are respectively disposed on the anode surface and the cathode surface of the proton membrane layer 11.

[0041] In some embodiments, the splicing layer 26 is bonded together in a flat manner to facilitate adjacency and adhesion.

[0042] In other embodiments, one of the frame film layers 2 includes multiple splicing layers 26 that are bonded together with each other, and the frame film layer 2 is disposed on the cathode surface of the proton membrane layer 11; the other frame film layer 2 is an integrally formed film layer, and the frame film layer 2 is disposed on the anode surface of the proton membrane layer 11.

[0043] In some embodiments, the splicing layers 26 can be bonded together using adhesives such as hot melt adhesive or pressure-sensitive adhesive.

[0044] like Figures 3 to 4 As shown, in some embodiments of the present invention, the frame film layer 2 includes two end film layers 24 spaced apart along its length direction and two side film layers 25 spaced apart along its width direction, with all end film layers 24 and all side film layers 25 surrounding the opening 21.

[0045] Specifically, all end membrane layers 24 and all side membrane layers 25 are distributed around the catalyst layer 12, and all end membrane layers 24 and all side membrane layers 25 can provide support, protection, sealing and insulation for the membrane electrode layer 1.

[0046] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments of this utility model, the two frame film layers 2 are respectively a first frame film layer 22 and a second frame film layer 23. The first frame film layer 22 is disposed on the anode surface of the proton exchange membrane layer 11, and the thickness of the first frame film layer 22 is equal to the thickness of the splicing layer 26. The first frame film layer 22 is integrally formed. The second frame film layer 23 is disposed on the cathode surface of the proton exchange membrane layer 11. The second frame film layer 23 includes multiple splicing layers 26 that are bonded and spliced ​​together. The thickness of the second frame film layer 23 is at least twice the thickness of the splicing layer 26.

[0047] Specifically, although adding the border film layer 2 can improve the protection of the membrane electrode layer 1, the raw material cost of the border film layer 2 is high, and excessively increasing the thickness of the border film layer 2 will reduce the heat dissipation effect. Therefore, the overall thickness of the first border film layer 22 and the second border film layer 23 should not be too high. Therefore, only the thickness of the second border film layer 23 can be increased, while the thickness of the first border film layer 22 remains unchanged. That is, the first border film layer 22 is still made by cutting the film material as a whole, thus moderately increasing the overall thickness of the two border film layers 2 and preventing the overall thickness of the two border film layers 2 from being too high. Moreover, the second border film layer 23 is composed of multiple splicing layers 26, which are derived from the leftover material generated from cutting the first border film layer 22. Therefore, the cost of the second border film layer 23 will not be high, thereby avoiding a significant increase in manufacturing costs. Preferably, the thickness of the second border film layer 23 is 2 or 3 times the thickness of the splicing layers 26.

[0048] like Figures 4 to 7As shown, in some embodiments of this utility model, the multiple splicing layers 26 include multiple first splicing layers 261 and multiple second splicing layers 262. The side film layer 25 of the second border film layer 23 includes a first outer layer portion 251, a middle layer portion 252, and a second outer layer portion 253 distributed sequentially along its thickness direction. The first outer layer portion 251, the middle layer portion 252, and the second outer layer portion 253 each include multiple first splicing layers 261 that are sequentially laid and adjacent to each other along the length direction of the second border film layer 23. All the first splicing layers 261 of the first outer layer portion 251 are staggered from all the first splicing layers 261 of the middle layer portion 252, and all the first splicing layers 261 of the second outer layer portion 253 are staggered from all the first splicing layers 261 of the middle layer portion 252.

[0049] Specifically, the middle layer 252 is located between the first outer layer 251 and the second outer layer 253. One of the first outer layer 251 and the second outer layer 253 is bonded to the membrane electrode layer 1, and the other is bonded to the bipolar plate. In addition, all the first splicing layers 261 of the first outer layer 251 are staggered from all the first splicing layers 261 of the middle layer 252, and all the first splicing layers 261 of the second outer layer 253 are staggered from all the first splicing layers 261 of the middle layer 252, thereby increasing the structural strength and stability of the side membrane layer 25.

[0050] In some embodiments, the side film layer 25 of the second frame film layer 23 may include only the first outer layer portion 251 and the middle layer portion 252, or only the middle layer portion 252 and the second outer layer portion 253.

[0051] like Figure 5 As shown, in some embodiments of the present invention, the end film layer 24 of the second frame film layer 23 includes three second splicing layers 262 stacked along its thickness direction. The three second splicing layers 262 are respectively adjacent to the first splicing layer 261 of the first outer layer portion 251, the first splicing layer 261 of the middle layer portion 252, and the first splicing layer 261 of the second outer layer portion 253.

[0052] Specifically, the three second splicing layers 262 are respectively matched with the first outer layer 251, the middle layer 252 and the second outer layer 253 to make the end film layer 24 and the side film layer 25 form a whole with uniform thickness.

[0053] like Figure 5 and Figure 7 As shown, in some embodiments of this utility model, one of the middle second splicing layers 262 is provided with two clearance notches 263. The two clearance notches 263 are distributed at intervals along the width direction of the second frame film layer 23, and the first splicing layers 261 of the two middle layer portions 252 extend into the two clearance notches 263 respectively.

[0054] Specifically, the first splicing layer 261 of the middle layer 252 extends into the clearance notch 263, and the first splicing layer 261 is bonded together with the two second splicing layers 262 on both sides, thereby connecting the end film layer 24 and the side film layer 25 into a structurally stable whole, enhancing the structural strength and stability of the second frame film layer 23.

[0055] like Figure 5 and Figure 7 As shown, in some embodiments of the present invention, another second splicing layer 262 located in the middle extends between the first splicing layer 261 of the first outer layer portion 251 and the first splicing layer 261 of the second outer layer portion 253.

[0056] Specifically, for the other end film layer 24, the middle second splicing layer 262 is provided with two extensions 264. These two extensions 264 extend to the space between the first splicing layer 261 of the first outer layer portion 251 and the first splicing layer 261 of the second outer layer portion 253, respectively. The second splicing layer 262 is bonded to the first splicing layers 261 on both sides, thereby connecting the end film layer 24 and the side film layer 25 into a structurally stable whole, enhancing the structural strength and stability of the second frame film layer 23.

[0057] like Figure 7 As shown, in some embodiments of the present invention, the first splicing layer 261 of the middle layer portion 252 is provided with an elongated hole 265 extending along its length direction. The elongated hole 265 is disposed between the seams of adjacent first splicing layers 261, and the width of the elongated hole 265 is less than or equal to the thickness of the first splicing layer 261.

[0058] Specifically, the adhesive between the first outer layer 251 and the middle layer 252, and the adhesive between the second outer layer 253 and the middle layer 252, can be connected together through elongated holes 265, thereby connecting the side film layers 25 into a structurally stable whole and enhancing the structural strength and stability of the second frame film layer 23. Furthermore, during the process of laying the first splicing layer 261, wrinkles may form in the first splicing layer 261 of the middle layer 252; the elongated holes 265 facilitate the smoothing of these wrinkles. Moreover, the elongated holes 265 can also accommodate tiny air bubbles that are difficult to detect, ensuring that the first splicing layer 261 adheres fully.

[0059] In some embodiments, the second splicing layer 262 located in the middle may also be provided with a strip-shaped hole, the width of which is less than or equal to the thickness of the second splicing layer 262. This strip-shaped hole can also achieve the beneficial effects of the elongated hole 265, which will not be elaborated upon in this invention.

[0060] This utility model also provides a battery unit, which includes two bipolar plates and a membrane electrode assembly as described in the above embodiment, wherein the membrane electrode assembly is disposed between the two bipolar plates.

[0061] Specifically, the battery cell uses the aforementioned membrane electrode assembly, so the battery cell can also achieve the beneficial effects of the above embodiments.

[0062] This invention also provides a battery stack, which includes a plurality of battery cells described in the above embodiments.

[0063] Specifically, the battery stack uses the aforementioned battery cells, so the battery stack can also achieve the beneficial effects of the above embodiments.

[0064] The various embodiments of this utility model have now been described in detail. To avoid obscuring the concept of this utility model, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solution of this utility model based on the above description.

[0065] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any manner.

Claims

1. A membrane electrode assembly, characterized by, include: A membrane electrode layer (1) comprising a proton membrane layer (11), wherein a catalyst layer (12) is provided at the center of both sides of the proton membrane layer (11), and a carbon paper layer (13) is provided on the side of the catalyst layer (12) opposite to the proton membrane layer (11), wherein the carbon paper layer (13) completely covers the corresponding catalyst layer (12); and Two frame film layers (2) are provided, and a membrane electrode layer (1) is disposed between the two frame film layers (2). The middle part of the frame film layer (2) is provided with an opening (21) corresponding to the catalyst layer (12). The frame film layer (2) is distributed around the catalyst layer (12). The periphery of the carbon paper layer (13) is attached to the corresponding frame film layer (2). The periphery of the proton membrane layer (11) is attached to the frame film layer (2). The frame film layer (2) has a uniform thickness. At least one frame film layer (2) includes multiple splicing layers (26) that are bonded together. The thickness of the frame film layer (2) including multiple splicing layers (26) is greater than the thickness of the splicing layer (26). At least the cathode surface of the proton membrane layer (11) is provided with the frame film including multiple splicing layers (26).

2. The membrane electrode assembly according to claim 1, characterized in that, The border film layer (2) includes two end film layers (24) spaced apart along its length direction and two side film layers (25) spaced apart along its width direction, all of the end film layers (24) and all of the side film layers (25) surrounding the opening (21).

3. The membrane electrode assembly according to claim 2, characterized in that, The two frame film layers (2) are a first frame film layer (22) and a second frame film layer (23), respectively. The first frame film layer (22) is disposed on the anode surface of the proton membrane layer (11), and the thickness of the first frame film layer (22) is equal to the thickness of the splicing layer (26). The first frame film layer (22) is integrally formed. The second frame film layer (23) is disposed on the cathode surface of the proton membrane layer (11). The second frame film layer (23) includes multiple splicing layers (26) that are bonded together with each other. The thickness of the second frame film layer (23) is at least twice the thickness of the splicing layer (26).

4. The membrane electrode assembly according to claim 3, characterized in that, The multiple splicing layers (26) include multiple first splicing layers (261) and multiple second splicing layers (262); The side film layer (25) of the second border film layer (23) includes a first outer layer portion (251), a middle layer portion (252) and a second outer layer portion (253) distributed sequentially along its thickness direction; the first outer layer portion (251), the middle layer portion (252) and the second outer layer portion (253) each include multiple first splicing layers (261) that are sequentially laid and adjacent to each other along the length direction of the second border film layer (23), all the first splicing layers (261) of the first outer layer portion (251) are staggered from all the first splicing layers (261) of the middle layer portion (252), and all the first splicing layers (261) of the second outer layer portion (253) are staggered from all the first splicing layers (261) of the middle layer portion (252).

5. The membrane electrode assembly according to claim 4, characterized in that, The end film layer (24) of the second border film layer (23) includes three second splicing layers (262) stacked along its thickness direction. The three second splicing layers (262) are respectively adjacent to the first splicing layer (261) of the first outer layer portion (251), the first splicing layer (261) of the middle layer portion (252) and the first splicing layer (261) of the second outer layer portion (253).

6. The membrane electrode assembly according to claim 5, characterized in that, One of the second splicing layers (262) located in the middle has two clearance notches (263). The two clearance notches (263) are distributed at intervals along the width direction of the second border film layer (23). The first splicing layers (261) of the two middle layer portions (252) extend into the two clearance notches (263) respectively.

7. The membrane electrode assembly according to claim 6, characterized in that, Another second splicing layer (262) located in the middle extends between the first splicing layer (261) of the first outer layer portion (251) and the first splicing layer (261) of the second outer layer portion (253).

8. The membrane electrode assembly according to claim 4, characterized in that, The first splicing layer (261) of the middle layer (252) is provided with an elongated hole (265) extending along its length direction. The elongated hole (265) is disposed between the seams of adjacent first splicing layers (261), and the width of the elongated hole (265) is less than or equal to the thickness of the first splicing layer (261).

9. A battery cell, characterized in that, The battery cell includes two bipolar plates and a membrane electrode assembly according to any one of claims 1-8, wherein the membrane electrode assembly is disposed between the two bipolar plates.

10. A fuel cell stack, characterized in that, The stack includes a plurality of battery cells as described in claim 9.

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