Simple fuel cell membrane electrode assembly and fuel cell

Abstract

The utility model provides a kind of simple fuel cell membrane electrode assembly and fuel cell, including proton exchange membrane and the electrode of being arranged in the both sides of proton exchange membrane, the outside of the electrode is equipped with U-shaped frame, and the end of proton exchange membrane and electrode is all contacted the inner bottom of U-shaped frame.The utility model uses "U" shaped frame to replace traditional multilayer composite structure, so that proton exchange membrane and electrode are just embedded in "U" shaped frame, avoid the performance of electrode to be easily influenced by deviation produced by multiple precision alignment;And it is convenient for U-shaped frame and electrode to be tightly combined by hot-pressing embedding process, improve assembly efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of batteries, and in particular to a membrane electrode assembly for a fuel cell. Background Technology

[0002] A fuel cell is an energy conversion device that converts the chemical energy of fuel into electrical energy through a redox reaction. A hydrogen fuel cell uses hydrogen as fuel and converts the chemical energy of hydrogen into electrical energy through an electrochemical reaction. Its electrochemical reaction product is water, and the entire reaction process does not pollute the environment. The most representative type of hydrogen fuel cell is the proton exchange membrane (PEM) fuel cell. Generally, a hydrogen fuel cell consists of multiple PEM fuel cell cells. Each PEM fuel cell cell includes at least an anode plate, a cathode plate, and a membrane electrode assembly (MEA) disposed between the anode and cathode plates. Multiple fuel cell cells are stacked to form a fuel cell unit.

[0003] The membrane electrode assembly (MEA) is a key component in fuel cell power generation. A fuel cell MEA typically consists of a proton exchange membrane, a catalyst layer, a gas diffusion layer, and a sealing frame. Currently, the main method for fabricating MEAs is to cold-bond or hot-press a pre-prepared three-in-one electrode with a double-layer or single-layer frame material to form a five-in-one electrode, and then bond cathode / anode carbon paper to both sides of the five-in-one electrode to form a seven-in-one electrode. The electrode cutting and shaping process is generally performed after the five-in-one or seven-in-one process. Furthermore, in traditional fuel cell assembly, the frame often employs a multi-layer design, commonly including upper and lower frames, and a middle frame. This multi-layer design makes the electrode structure extremely complex. Precise alignment is required during assembly; any slight deviation can affect the electrode performance. Moreover, multiple pressing processes are indispensable, which not only increases the complexity of the operation but also consumes a significant amount of time.

[0004] The membrane electrode frame structure mentioned above also has some drawbacks: usually, the proton exchange membrane extends to the outer edge of the electrode frame, which significantly reduces the utilization rate of the proton exchange membrane and increases the manufacturing cost of the membrane electrode. Summary of the Invention

[0005] To address the aforementioned technical problems, this utility model proposes a simplified fuel cell membrane electrode assembly and fuel cell, which solves the problems in the prior art where the membrane electrode frame structure requires precise alignment, which can easily lead to deviations that affect electrode performance and reduce the utilization rate of the proton exchange membrane.

[0006] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0007] A simplified fuel cell membrane electrode assembly includes a proton exchange membrane and electrodes disposed on both sides of the proton exchange membrane. A U-shaped frame is provided on the outer side of the electrodes, and the ends of both the proton exchange membrane and the electrodes contact the inner bottom of the U-shaped frame. This invention uses an integrated U-shaped frame to replace the traditional multi-layer composite structure, avoiding deviations that can easily occur during repeated precision alignment and affect electrode performance. Furthermore, it facilitates a tight bond between the U-shaped frame and the electrodes through a hot-pressing embedding process, improving assembly efficiency.

[0008] Furthermore, in order to better support the electrode, the U-shaped frame covers the outer side of one end of the electrode and the proton exchange membrane, and carbon paper is provided on the outer side of the other end of the electrode.

[0009] Furthermore, in order to facilitate the fixing of the carbon paper to the outside of the electrode, the carbon paper is pasted on the outside of the electrode.

[0010] Furthermore, in order to ensure that the U-shaped frame and carbon paper completely cover the outer side of the electrode, the opening of the U-shaped frame is bonded to the carbon paper with adhesive.

[0011] Furthermore, in order to ensure a secure seal between the U-shaped frame and the electrodes and proton exchange membrane, a hot melt adhesive layer is pre-coated inside the U-shaped frame.

[0012] Furthermore, in order to facilitate a tight fit between the frame and the film layer, the U-shaped frame is an integrated elastic frame made of polymer elastic material.

[0013] Furthermore, the electrode includes a cathode and an anode respectively disposed on both sides of the proton exchange membrane, and both the cathode and the anode include a catalyst layer and a gas diffusion layer; and the catalyst layer is sandwiched between the gas diffusion layer and the proton exchange membrane.

[0014] Furthermore, to prevent corrosion caused by direct contact between the catalyst layer and the frame, the two ends of the gas diffusion layer are flush with the two ends of the proton exchange membrane, and the length of the catalyst layer along the length direction of the proton exchange membrane is less than the length of the proton exchange membrane.

[0015] Furthermore, the distance between the catalyst layer and the corresponding end of the proton exchange membrane along the length of the proton exchange membrane is 2-4 mm.

[0016] Furthermore, the inner bottom of the U-shaped frame is a flat bottom that fits into the ends of the gas diffusion layer and the proton exchange membrane.

[0017] Furthermore, the U-shaped frame is pressed together with the proton exchange membrane and the gas diffusion layer by a hot-pressing process.

[0018] A fuel cell comprising the simplified fuel cell membrane electrode assembly described in any of the preceding claims.

[0019] The beneficial effects of this utility model are:

[0020] 1. This utility model adopts an integrally molded "U"-shaped frame to replace the traditional multi-layer composite structure, and combines hot-pressing embedding process to improve assembly efficiency.

[0021] 2. This utility model effectively solves the air leakage risk caused by uneven glue distribution in traditional processes by pre-placing a hot melt adhesive layer inside the "U"-shaped frame to form a uniform sealing interface after heating.

[0022] 3. By making the area of ​​the catalyst layer smaller than that of the gas diffusion layer, this utility model can prevent the catalyst layer from directly contacting the frame and causing corrosion.

[0023] 4. This utility model uses an integrated elastic frame made of polymer elastic material, which gives the U-shaped frame stress buffering characteristics and can effectively absorb the mechanical stress during the battery stacking process. Combined with the enhanced sealing structure, it improves the impact resistance of the proton exchange membrane under complex working conditions. The overall structure simplifies the process while enhancing reliability and optimizing overall cost. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram of the structure of this utility model.

[0026] In the diagram: 1. Proton exchange membrane; 2. Catalyst layer; 3. Gas diffusion layer; 4. U-shaped frame; 5. Carbon paper. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figure 1As shown in Embodiment 1 of this utility model, a simplified fuel cell membrane electrode assembly includes a proton exchange membrane 1 and electrodes disposed on both sides of the proton exchange membrane 1. The electrodes include a cathode and an anode respectively disposed on both sides of the proton exchange membrane 1. The cathode includes a catalyst layer 2 and a gas diffusion layer 3 located on one side of the proton exchange membrane 1, with the catalyst layer 2 sandwiched between the gas diffusion layer 3 and the proton exchange membrane 1. The anode includes a catalyst layer 2 and a gas diffusion layer 3 located on the other side of the proton exchange membrane 1, with the catalyst layer 2 also sandwiched between the gas diffusion layer 3 and the proton exchange membrane 1 on that side. Furthermore, the gas diffusion layer 3 and catalyst layer 2 of the cathode and anode are symmetrically disposed on both sides of the proton exchange membrane 1.

[0029] Furthermore, such as Figure 1 As shown, a U-shaped frame 4 is provided on the outer side of the electrode, and the opening direction of the U-shaped frame 4 is along the length direction of the proton exchange membrane. The gas diffusion layer 3 and the proton exchange membrane 1, together with the catalyst layer 2, are embedded in the opening of the U-shaped frame 4, so that the U-shaped frame 4 covers the outside of the proton exchange membrane 1 and the gas diffusion layers 3 on both sides, and at the same time, one end of the proton exchange membrane 1 and the gas diffusion layer 3 of the electrode are in contact with the inner bottom of the U-shaped frame 4.

[0030] Furthermore, such as Figure 1 As shown, the U-shaped frame 4 covers the left end and the outer side near the left end of the electrode and proton exchange membrane 1, and carbon paper 5 is provided on the outer side of the right end of the electrode. In this embodiment, the carbon paper 5 is attached to the outside of the gas diffusion layer 3 of the two electrodes.

[0031] Furthermore, the opening of the U-shaped frame 4 is bonded to the carbon paper 5 with adhesive, so that the U-shaped frame and the carbon paper 5 cover the entire outer surface of the gas diffusion layer 3. At the same time, the left end face of the gas diffusion layer 3 and the proton exchange membrane 1 is completely located inside the U-shaped frame, while the right end face of the gas diffusion layer 3 and the proton exchange membrane 1 is exposed outside the carbon paper 5.

[0032] The U-shaped frame 4 and the carbon paper 5 can be bonded together using at least one of hot melt adhesive, UV adhesive, acrylic adhesive, pressure-sensitive adhesive, and silicone.

[0033] Example 2 differs from Example 1 in that a hot melt adhesive layer is pre-coated inside the U-shaped frame 4. By pre-coating the hot melt adhesive layer, after the gas diffusion layer 3 and the proton exchange membrane 1, along with the catalyst layer 2, are embedded inside the U-shaped frame, the hot melt adhesive layer melts and then solidifies upon heating to form a uniform sealing interface when the membrane layers are fixed using a hot-pressing process. This effectively solves the problem of uneven adhesive distribution leading to air leakage in traditional processes.

[0034] In this embodiment, during hot pressing, the temperature is heated to 120°C-150°C using a hot pressing device, causing the pre-coated hot melt adhesive layer to melt and wrap around the edge of the film layer.

[0035] Example 3 differs from Example 2 in that the U-shaped frame 4 is an integrated elastic frame made of a polymer elastic material. The polymer elastic material gives the U-shaped frame better stress-buffering properties, effectively absorbing mechanical stress during the battery stack pressing process. Combined with the enhanced sealing structure, this improves the impact resistance of the proton exchange membrane under complex operating conditions. The overall structure simplifies the process while enhancing reliability and optimizing overall cost. In this example, the U-shaped frame 4 is made of silicone rubber or fluororubber, which is corrosion-resistant and elastic, suitable for the high-temperature and high-humidity environment of fuel cells.

[0036] Example 4 differs from Example 3 in that, as Figure 1 As shown, the two ends of the gas diffusion layer 3 are flush with the two ends of the proton exchange membrane 1. The catalyst layer 2 is sandwiched between the gas diffusion layer 3 and the proton exchange membrane 1. At the same time, the length of the catalyst layer 2 along the length direction of the proton exchange membrane 1 is less than the length of the proton exchange membrane 1, so that the part of the gas diffusion layer 3 near the end is completely attached to the part of the proton exchange membrane 1 near the end, sealing the catalyst layer inside and preventing the catalyst layer from directly contacting the frame and causing corrosion.

[0037] In this embodiment, the distance between the catalyst layer 2 and the corresponding end of the proton exchange membrane 1 along the length direction is 2-4 mm.

[0038] Example 5 differs from Example 4 in that, as Figure 1 As shown, the inner bottom of the U-shaped frame is a flat bottom that fits with the ends of the gas diffusion layer 3 and the proton exchange membrane 1, and the space inside the U-shaped frame fits the proton exchange membrane 1 and the electrodes on both sides, so that the membrane electrode assembly forms a sealed structure after hot pressing and curing. The elastic material of the U-shaped frame 4 is tightly attached to the membrane layer without the need for additional bolts.

[0039] Example 6: A fuel cell comprising the simplified fuel cell membrane electrode assembly described in any of the preceding embodiments.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some or all of the technical features thereof, within the spirit and principles of the present invention, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A simple fuel cell membrane electrode assembly, comprising a proton exchange membrane (1) and electrodes disposed on both sides of the proton exchange membrane (1), characterized in that, The electrode has a U-shaped frame (4) on its outer side, and the proton exchange membrane (1) and the end of the electrode are in contact with the inner bottom of the U-shaped frame (4).

2. The simplified fuel cell membrane electrode assembly according to claim 1, characterized in that, The U-shaped frame (4) covers one end of the electrode and the proton exchange membrane (1), and carbon paper (5) is pasted on the other end of the electrode.

3. The simplified fuel cell membrane electrode assembly according to claim 2, characterized in that, The opening of the U-shaped frame (4) is bonded to the carbon paper (5) with adhesive.

4. The simplified fuel cell membrane electrode assembly according to any one of claims 1 to 3, characterized in that, The U-shaped frame (4) is pre-coated with a hot melt adhesive layer.

5. The simplified fuel cell membrane electrode assembly according to claim 4, characterized in that, The U-shaped frame (4) is an integrated elastic frame made of polymer elastic material.

6. The simplified fuel cell membrane electrode assembly according to any one of claims 1 to 3 and 5, characterized in that, The electrode includes a cathode and an anode respectively disposed on both sides of the proton exchange membrane (1), and both the cathode and the anode include a catalyst layer (2) and a gas diffusion layer (3); and the catalyst layer (2) is sandwiched between the gas diffusion layer (3) and the proton exchange membrane (1).

7. The simplified fuel cell membrane electrode assembly according to claim 6, characterized in that, The two ends of the gas diffusion layer (3) are flush with the two ends of the proton exchange membrane (1), and the length of the catalyst layer (2) along the length direction of the proton exchange membrane (1) is less than the length of the proton exchange membrane (1).

8. The simplified fuel cell membrane electrode assembly according to claim 7, characterized in that, The catalyst layer (2) is 2-4 mm away from the corresponding ends of the proton exchange membrane (1) at both ends along the length of the proton exchange membrane (1).

9. The simplified fuel cell membrane electrode assembly according to claim 7 or 8, characterized in that, The inner bottom of the U-shaped frame (4) is a flat bottom that fits into the ends of the gas diffusion layer (3) and the proton exchange membrane (1).

10. A fuel cell, characterized in that, Includes the simplified fuel cell membrane electrode assembly as described in any one of claims 1 to 9.

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