CN111477912A - Membrane electrode packaging structure and packaging method - Google Patents

Abstract

The invention relates to the field of fuel cells, in particular to a membrane electrode packaging structure and a packaging method. The membrane electrode packaging structure includes a gas diffusion layer on the top surface and a gas diffusion layer on the bottom surface, a frame and a catalyst coating film stacked on each other are sandwiched between the two gas diffusion layers, the catalyst coating film is bonded and fixed on the top surface of the frame, and the frame There is only one, the top surface of the frame where the catalyst coating film is bonded is recessed, the catalyst coating film is bonded on the bottom wall of the recess, and the inner sidewall of the recess blocks the circumference of the catalyst coating film. The packaging structure can reduce the production cost and reduce the risk of air leakage in the sealing area.

Description

Membrane electrode packaging structure and packaging method

technical field

The invention relates to the field of fuel cells, in particular to a membrane electrode packaging structure and a packaging method.

Background technique

As shown in Figure 1, the current mainstream packaging method for membrane electrodes is as follows: first, the anode catalyst layer and the cathode catalyst layer are respectively coated on both ends of the proton exchange membrane to prepare a catalyst coating membrane 4 (CCM) with a three-layer structure; The edge of the catalyst coating film 4 and the edges of the two frames 1 and 9 are bonded and sealed by an adhesive to form a five-layer assembly; the last two gas diffusion layers 5 and 6 are respectively bonded to the frames by an adhesive. A seven-layer membrane electrode is formed.

Although the above double-layer frame membrane electrodes can meet the basic sealing requirements, they have the following two main disadvantages in large-scale mass production:

(1) High cost:

Because it is a double-layer frame structure, the amount of frame materials and adhesives used is large, and the cost is high for mass production, especially because the working environment of the fuel cell involves high and low humidity cycles, high and low temperature cycles, and strong chemical corrosion. (Free radicals) and other harsh conditions require the use of special-purpose adhesives. The development and production costs of such adhesives are high, so if the amount of adhesive used is large, the cost is high.

(2) The difficulty of quality control is high:

①When pre-coating glue on the frame, there may be uneven phenomenon. For example, there are defects such as no glue and little glue in some areas, which can easily make the gas on the side of the catalyst coating film break through the sealing structure formed by the adhesive layer. Leakage to the other side of the catalyst-coated membrane results in outgassing and affects performance.

②As shown in Fig. 2, when the two layers of frames 1, 9 and the catalyst coating film 4 are pressed together after pre-gluing, there may be uneven pressing force, which may cause defects. For example, in the first adhesive 3 The presence of the air bubbles 10 may also cause the gas on one side of the catalyst coating film 4 to leak through the air bubbles 10 in the first adhesive 3 to the other side of the catalyst coating film, resulting in gas leakage. Although the defects such as air bubbles can be alleviated to a certain extent by improving the pressing methods, such as using rolling instead of flat pressing and pre-vacuuming, it is still difficult to completely solve the air-bubble problem, and pre-vacuuming is also time-consuming. time and reduce production efficiency.

③ After pre-gluing, when the two-layer frame 1, 9 and the catalyst coating film 4 are pressed together, deformation and displacement are likely to occur, so that accurate alignment cannot be achieved.

SUMMARY OF THE INVENTION

The present invention provides a membrane electrode packaging structure and a packaging method. The packaging structure can reduce production cost and have low risk of gas leakage.

In order to reduce the amount of frame and adhesive used, the inventor designed a membrane electrode packaging structure with a single-layer frame. The exploded view of the membrane electrode packaging structure with a single-layer frame is shown in Figure 3, including the top surface gas diffusion layer 5 arranged in sequence. , the catalyst coating film 4 , the frame 1 and the bottom gas diffusion layer 6 . Compared with the traditional double-layer frame membrane electrode packaging structure, although this structure only uses one layer of frame 1, not only the amount of frame material is reduced, but also the amount of adhesive used is also significant due to the reduction in the number of adhesive layers. reduce, reduce costs. However, the inventors found that since only one side of the catalyst coating film 4 is adhered to the frame 1, during the assembly and operation of the fuel cell, the catalyst coating film 4 will be damaged due to external mechanical force and internal swelling tension caused by drying and wetting cycles. Displacement occurs, resulting in air leakage from the sealing structure formed by the first adhesive 3 (see FIG. 4 ), and the stack fails. Moreover, as shown in Figure 4, the package structure will generate higher mechanical stress in the overlapping area of the top surface gas diffusion layer 5-catalyst coating film 4-frame 1 than the surrounding area (the stress direction is shown by the arrow in Figure 4), It will cause: (1) the edge of the proton exchange membrane in the catalyst coating film 4 is mechanically degraded; (2) the catalyst coating film 4 falls off from the frame 1; (3) the top surface gas diffusion layer 5 is opposite to the catalyst coating film 4 Physical damage occurs, and the above three situations will eventually lead to the failure of the sealing of the membrane electrode, resulting in air leakage.

In order to achieve the above object, the present invention adopts the following technical solutions:

A membrane electrode packaging structure comprises a gas diffusion layer on a top surface and a gas diffusion layer on a bottom surface, a frame and a catalyst coating film stacked on each other are sandwiched between the two gas diffusion layers, and the catalyst coating film is bonded and fixed on the top surface of the frame, There is only one frame, the top surface of the frame where the catalyst coating film is bonded is recessed, the catalyst coating film is bonded on the bottom wall of the recess, and the inner sidewall of the recess blocks the circumference of the catalyst coating film.

Further, the inner sidewall of the depression abuts the side surface of the catalyst coating film to prevent the catalyst coating film from being displaced and displaced laterally.

Further, the bottom wall surface of the depression is rough.

Further, the catalyst coating film is bonded to the bottom wall of the depression through the first adhesive layer, and the gas diffusion layer on the top surface is bonded to the non-depression on the top surface of the frame through the second adhesive layer and covers the catalyst coating. On the top surface of the cloth film, the sum of the thicknesses of the inner sidewall of the depression and the second adhesive layer is not less than the sum of the thicknesses of the first adhesive layer and the catalyst coating film, so that the top surface is The gas diffusion layer is integrally bonded to the frame evenly, and the bottom gas diffusion layer is bonded to the bottom surface of the frame.

Further, the sum of the thickness values of the inner sidewall of the depression and the second adhesive layer is equal to the sum of the thicknesses of the first adhesive layer and the catalyst coating film.

A membrane electrode packaging method includes the following steps:

Concave construction step: only one frame is used, and a depression is constructed on the top surface of the frame for the catalyst coating film to sink into and bond;

Catalyst coating film bonding step: place the catalyst coating film in the area enclosed by the inner side wall of the depression, so that the bottom surface of the catalyst coating film is bonded to the bottom wall of the depression, and the inner side wall of the depression is sealed. Blocking around the catalyst coating film;

The gas diffusion layer bonding step: the top gas diffusion layer is bonded to the non-recess on the top surface of the frame, so that the top gas diffusion layer covers the top surface of the catalyst coating film, and the bottom gas diffusion layer is bonded to the bottom surface of the frame , so that the bottom gas diffusion layer on the bottom surface covers the bottom surface of the catalyst coating film.

Further, in the step of constructing the depression, specifically: the area enclosed by the inner sidewall of the depression is the same in shape and size as the catalyst coating film, so that the inner sidewall of the depression is pressed against the side surface of the catalyst coating film to prevent the catalyst coating. The cloth film is laterally offset and misaligned.

Further, the top surface gas diffusion layer is bonded to the non-recessed place on the top surface of the frame through the second adhesive layer, the bottom surface gas diffusion layer is bonded to the bottom surface of the frame through the third adhesive layer, and the inner side wall of the depression is connected to the bottom surface of the frame. The sum of the thicknesses of the second adhesive layer is not less than the sum of the thicknesses of the first adhesive layer and the catalyst coating film, so that the top-surface gas diffusion layer is adhered to the frame evenly as a whole.

Further, the sum of the thickness values of the inner sidewall of the depression and the second adhesive layer is equal to the sum of the thicknesses of the first adhesive layer and the catalyst coating film.

Further, in the step of constructing the depression, the depression is constructed by etching on the top surface of the frame.

Beneficial effects: Since there is only one frame to bond the catalyst coating film, the frame material and the adhesive material are saved, and the cost is saved; the inner side wall of the depression blocks the circumference of the catalyst coating film, which can prevent the production and use of the film on the one hand. During the process, the catalyst coating film and the frame are displaced from each other, which is convenient for production and reduces the air leakage caused by the dislocation. Defects, after the gas on one end of the catalyst coating film reaches the side of the catalyst coating film through defects such as bubbles, it will be blocked by the inner sidewall of the depression and cannot leak to the other end surface, thus reducing the possibility of gas leakage.

Description of drawings

Figure 1 is an exploded view of a membrane electrode structure with a double-layer frame;

Fig. 2 is a structural diagram of a frame and a catalyst coating film in a double frame film electrode structure;

FIG. 3 is an exploded view of the membrane electrode structure of the single-layer frame;

FIG. 4 is a package structure diagram of a single-layer frame film electrode made by a traditional packaging method;

FIG. 5 is a schematic diagram of the packaging process of the single-layer frame film electrode of the present embodiment;

Fig. 6 is the front view after the recess is formed on the frame;

FIG. 7 is a structural diagram of the package of the single-layer frame film electrode of the present embodiment.

Detailed ways

The specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention.

As shown in Figure 5, the membrane electrode packaging method includes the following steps:

① Only one frame 1 is used, and surface plasma etching or laser etching is performed on the top surface of frame 1 to construct a depression 2. The area enclosed by the inner sidewall 21 of the depression 2 (the area enclosed by the dotted line in Figure 6) and the catalyst The shape and size of the coating film 4 are the same, and the thickness value of the inner sidewall 21 at the depression 2 is equal to the thickness value of the catalyst coating film 4;

② Coat a layer of first adhesive 3 with a thickness of 3 to 20 microns on the bottom wall 22 of the depression 2, and the first adhesive 3 is in contact with the inner side wall 21 of the depression 2;

③ Put the catalyst coating film 4 into the area enclosed by the inner side wall 21 of the depression 2, and the inner side wall 21 of the depression 2 is against the circumference of the catalyst coating film 4, thereby blocking the catalyst coating film 4. Around, it also prevents the catalyst coating film 4 from being displaced laterally; and then according to the type of the first adhesive 3, the first adhesive 3 is cured by means of thermal curing, light curing or pressure curing to form an adhesive layer 3 , so that the bottom surface of the catalyst coating film 4 is bonded to the bottom wall 22 at the recess 2;

④ Coat the non-recessed part 11 of the top surface of the frame 1 with a second adhesive 7 with the same thickness as the first adhesive 3 layers, and bond the top surface gas diffusion layer 5 through the second adhesive 7 layers At the non-recessed portion 11 on the top surface of the frame 1, since the sum of the thicknesses of the inner sidewall 21 at the recessed portion 2 and the second adhesive layer 7 is equal to both the first adhesive layer 3 and the catalyst coating film 4 The sum of the thickness values of the second adhesive layer 7 and the upper surface of the catalyst coating film 4 are flush, so the top surface gas diffusion layer 5 is evenly bonded to the frame 1 and has the same thickness as the catalyst coating film 4. Contacting the top surface, that is, covering the top surface of the catalyst coating film 4;

⑤ Coat the bottom surface of the frame 1 with a layer of third adhesive 8, and bond the bottom surface gas diffusion layer 6 to the bottom surface of the frame 1 through the third adhesive 8 layer, so that the bottom surface gas diffusion layer 6 covers the catalyst coating film 4 the bottom surface.

After the membrane electrode packaging is completed, as shown in Figure 7, the first adhesive layer 3 bonds the bottom wall 22 of the depression 2 and the lower surface edge of the catalyst coating film 4 to form a first barrier to block the catalyst coating film. The air below 4 leaks to the top of the catalyst coating film 4, and since the surface of the bottom wall 22 at the recess 2 obtained by etching is rough, the first adhesive 3 has a strong adhesive force with the bottom wall 22 at the recess 2. , it is not easy to fall off from the bottom wall 22 of the depression 2, thus reducing the possibility of gas leakage from the bonding place between the first adhesive 3 and the bottom wall 22 of the depression 2; the inner side wall 21 of the depression 2 The side of the catalyst coating film 4 is pressed against the catalyst coating film 4 to block the circumference of the catalyst coating film 4 to form a second barrier, so that even if there are gas passages or air bubbles in the first barrier (ie, the first adhesive layer 3) , after the gas under the catalyst coating film 4 breaks through the first barrier, it will also be blocked by the second barrier (ie, the inner sidewall 21 at the recess 2), so that leakage will not occur. The sum of the thicknesses of the inner sidewall 21 at the depression 2 and the second adhesive layer 7 is equal to the sum of the thicknesses of the first adhesive layer 3 and the catalyst coating film 4, that is, the second adhesive The upper surface of the layer 7 and the catalyst coating film 4 are flush, so the top surface gas diffusion layer 5 is evenly bonded to the frame 1. In the overlapping area of the top surface gas diffusion layer 5-catalyst coating film 4-frame 1 It is subject to the same amount of stress as other surrounding areas (the direction of the stress is shown by the arrow in Figure 7), so the problem of uneven stress caused by the structure in Figure 4 will not occur, and it will not cause air leakage.

Not preferably, the thickness of the inner sidewall 21 at the groove 2 may not be equal to but greater than the thickness of the catalyst coating film 4. In this case, the top surface gas diffusion layer 5 is supported by the second adhesive layer 7. The lower surface is still flat as a whole, and there is no uneven stress, but it is not in contact with the catalyst coating film 4 .

Non-preferably, a fourth adhesive layer is provided between the inner side wall 21 of the groove 2 and the side surface of the catalyst coating film 4, so that the gas under the catalyst coating film 4 is more difficult to leak to the catalyst coating film 4 above. Although this kind of package structure has better air-leakage performance, it is an unpreferable way because an extra layer of the fourth adhesive is used, which will increase the cost.

The above descriptions are only the preferred embodiments of the present invention, and the present invention is not limited to the above-mentioned embodiments. There may be some minor structural changes in the implementation process. If various changes or modifications to the present invention do not depart from the spirit of the present invention The present invention also intends to include these changes and modifications.

Claims (10)

1. A membrane electrode packaging structure, comprising a gas diffusion layer on the top surface and a gas diffusion layer on the bottom surface, a frame and a catalyst coating film stacked on each other are sandwiched between the two gas diffusion layers, and the catalyst coating film is bonded and fixed on the top of the frame. It is characterized in that there is only one frame, the top surface of the frame is recessed at the part where the catalyst coating film is bonded, the catalyst coating film is bonded on the bottom wall of the depression, and the inner side wall of the depression blocks the catalyst coating film. around. 2 . The membrane electrode packaging structure according to claim 1 , wherein the inner sidewall of the depression abuts the side surface of the catalyst coating film to prevent lateral displacement and dislocation of the catalyst coating film. 3 . 3 . The membrane electrode package structure according to claim 1 , wherein the bottom wall of the recess has a rough surface. 4 . 4 . The membrane electrode package structure according to claim 1 , wherein the catalyst coating film is adhered to the bottom wall of the depression through the first adhesive layer, and the gas diffusion layer on the top surface is bonded to the bottom wall of the depression. 5 . The second adhesive layer is bonded to the non-recessed part of the top surface of the frame and covers the top surface of the catalyst coating film. The sum of the thicknesses of the adhesive layer and the catalyst coating film enables the top gas diffusion layer to be bonded to the frame evenly as a whole, and the bottom gas diffusion layer to be bonded to the bottom of the frame. 5 . The membrane electrode packaging structure according to claim 4 , wherein the sum of the thicknesses of the inner sidewall of the recess and the second adhesive layer is equal to the thickness of the first adhesive layer and the catalyst coating film. 6 . The sum of the thickness values of the 6. A membrane electrode packaging method, characterized in that, comprising the following steps: Concave construction step: only one frame is used, and a depression is constructed on the top surface of the frame for the catalyst coating film to sink into and bond; Catalyst coating film bonding step: place the catalyst coating film in the area enclosed by the inner side wall of the depression, so that the bottom surface of the catalyst coating film is bonded to the bottom wall of the depression, and the inner side wall of the depression is sealed. Blocking around the catalyst coating film; The gas diffusion layer bonding step: the top gas diffusion layer is bonded to the non-recess on the top surface of the frame, so that the top gas diffusion layer covers the top surface of the catalyst coating film, and the bottom gas diffusion layer is bonded to the bottom surface of the frame , so that the bottom gas diffusion layer on the bottom surface covers the bottom surface of the catalyst coating film. 7 . The membrane electrode packaging method according to claim 6 , wherein, in the step of constructing the depression, specifically: the area enclosed by the inner sidewall of the depression is the same in shape and size as the catalyst coating membrane, so that the depression is formed. 8 . The inner sidewall of the catalyst-coated film abuts the side of the catalyst-coated film to prevent the catalyst-coated film from being displaced and displaced laterally. 8 . The membrane electrode packaging method according to claim 6 , wherein the gas diffusion layer on the top surface is bonded to the non-recess on the top surface of the frame by a second adhesive layer, and the gas diffusion layer on the bottom surface is bonded by a third adhesive layer. 9 . The adhesive layer is bonded to the bottom surface of the frame, and the sum of the thicknesses of the inner sidewall of the depression and the second adhesive layer is not less than the sum of the thicknesses of the first adhesive layer and the catalyst coating film, thereby The gas diffusion layer on the top surface is adhered to the frame evenly as a whole. 9 . The membrane electrode packaging method according to claim 8 , wherein the sum of the thicknesses of the inner sidewall of the depression and the second adhesive layer is equal to the thickness of the first adhesive layer and the catalyst coating film. 10 . The sum of the thickness values of the 10 . The membrane electrode packaging method according to claim 6 , wherein, in the step of constructing the depression, the depression is constructed by etching on the top surface of the frame. 11 .

Images