Preparation method of prefabricated member, preparation method and system of membrane electrode and prefabricated member

Abstract

The invention provides a preparation method of a prefabricated member of a membrane electrode, a preparation method and system of the membrane electrode and the prefabricated member. The preparation method of the prefabricated member of the membrane electrode comprises the following steps: symmetrically positioning two gas diffusion sheets in two positioning cavities of an injection mold; injecting colloid into the peripheries of the two positioning cavities to form a frame with a sealing structure, and connecting the two gas diffusion sheets together; and preparing the membrane electrode prefabricated member. According to the preparation method of the membrane electrode prefabricated member, the gas diffusion sheet is firstly positioned in the positioning cavity, and then the colloid is injected into the mold cavity, so that the preparation of the membrane electrode prefabricated member is facilitated, the preparation process is simplified, and the product percent of pass is improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell technology, and in particular to a method for preparing a membrane electrode preform. The present invention also relates to a membrane electrode preparation method, a preform preparation system, and a preform. Background Art

[0002] The seals between the membrane electrode and bipolar plate are crucial components of proton exchange membrane fuel cell stacks, primarily providing sealing within the hydrogen fuel cell stack. Failure of these seals in hydrogen fuel cells can lead to gas and coolant leakage, impacting the fuel cell's normal operation and, in severe cases, causing safety issues.

[0003] Currently, seal molding is mainly divided into two directions: one is to mold the seal on the bipolar plate, and the other is to set the seal on the membrane electrode preform. The preform refers to the state of the membrane electrode before the CCM membrane (catalyst-coated membrane) is bonded. The main molding processes for seals currently include dispensing, screen printing, injection molding, etc. In the current mainstream direction, seals injected into the membrane electrode preform or bipolar plate have the following problems during the injection molding process:

[0004] When seals are formed by injection molding onto membrane electrode preforms, the proton membrane shrinks when the preform is heated during injection molding. This can cause changes in the size or flatness of the injection area, leading to poor seal formation. Furthermore, when the preform is heated during injection molding, the volatilization of the primer can easily poison the catalyst in the preform. Furthermore, the cost of the preform itself is high, and defective injection molding can render the membrane electrode inoperable, resulting in waste.

[0005] In the bipolar plate sealant injection method, the seal molding precision is low due to the influence of the bipolar plate's thickness uniformity and flatness. Since the bipolar plate itself is composed of two monopolar plates, the dimensional tolerance and flatness errors introduced by the bipolar plate molding process cannot be completely eliminated. The only solution is to maximize the dimensional accuracy and flatness of the bipolar plate preparation to reduce the impact of the injection molding on the seal molding precision caused by the bipolar plate size. Summary of the Invention

[0006] In view of this, the present invention aims to provide a method for preparing a membrane electrode preform, so as to facilitate the preparation of the membrane electrode preform and improve the qualified rate.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A method for preparing a membrane electrode preform, for preparing a membrane electrode preform, the preform preparation method comprising:

[0009] symmetrically positioning two gas diffusion sheets in two positioning cavities of the injection mold;

[0010] A colloid is injected into the periphery of the two positioning cavities to form a frame with a sealing structure. The two gas diffusion sheets are connected together through the frame to obtain the prefabricated component.

[0011] Furthermore, the step of injecting colloid into the periphery of the two positioning cavities to form a frame connecting the two gas diffusion sheets comprises:

[0012] The colloid is injected and then heated and solidified to form the frame, and the heating temperature T satisfies: 80° C. ≤ T ≤ 120° C.

[0013] Furthermore, the gas diffusion sheet is carbon paper or carbon cloth, and the colloid is injection-molded silica gel or injection-molded silicone rubber.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The method for preparing a membrane electrode preform described in the present invention can form a frame with a sealing structure on the gas diffusion layer by first positioning the gas diffusion plate in the positioning cavity and then injecting colloid into the mold cavity, so that the preform is easy to obtain. Compared with the traditional solution of forming a sealing structure on the membrane electrode preform and the bipolar plate, it is not only conducive to simplifying the preparation process of the preform, but also conducive to avoiding the problems caused by the formation of the sealing structure on the membrane electrode preform and the bipolar plate, thereby helping to improve the qualified rate of the membrane electrode, and the connection strength between the colloid and the gas diffusion layer, as well as the sealing structure and the frame is high, which is conducive to improving the performance of the membrane electrode.

[0016] Furthermore, the setting of the colloid heating temperature helps improve the molding effect and efficiency of the preform. Carbon paper and carbon cloth are low-cost and easy to implement. Injection-molded silicone and injection-molded silicone rubber both have good molding effects and help ensure the performance of the frame and sealing structure.

[0017] In addition, another object of the present invention is to provide a membrane electrode preparation method, including the preparation method of the preform as described above; and further comprising:

[0018] Connecting the CCM membrane to one of the gas diffusion sheets, and then folding the preform in half;

[0019] The preform is compacted to seal the CCM membrane between the two gas diffusion sheets to obtain a membrane electrode.

[0020] Furthermore, the two gas diffusion plates are symmetrically positioned in the positioning cavity of the injection mold, including: the two gas diffusion plates in the positioning cavity are in the same plane; the edges of each gas diffusion plate in the positioning cavity extend outward into the mold cavity outside the positioning cavity, and the colloid is injected into the mold cavity.

[0021] Furthermore, compacting the preform to seal the CCM membrane between the two gas diffusion sheets includes: compacting the preform by rolling the bonding area between the CCM membrane and the two gas diffusion sheets with a rolling cylinder.

[0022] The membrane electrode preparation method of the present invention is conducive to preparing the membrane electrode and improving the preparation efficiency by bonding the CCM membrane to the gas diffusion sheet, folding the preform in half, and compacting it.

[0023] Furthermore, the two gas diffusers within the positioning cavity are coplanar, enhancing membrane electrode performance. The edges of the gas diffusers extend outward into the mold cavity, increasing the connection area between the gas diffusers and further strengthening the connection between the gas diffusers and the frame. Positioning in a preset position is facilitated by the flow channel holes and positioning posts on the frame, ensuring ease of operation and effective positioning. A rolling cylinder compresses the bonding area around the CCM membrane and the two gas diffusers, enhancing the seal between the CCM membrane and the two gas diffusers.

[0024] In addition, another object of the present invention is to provide a preparation system, wherein the preform preparation system is used to perform the preform preparation method as described above, and the preform preparation system includes an injection mold;

[0025] The injection mold comprises an upper mold body and a lower mold body that are connected by snapping, and the two positioning cavities and the mold cavity located on the periphery of the positioning cavity (100) are formed between the upper mold body and the lower mold body, and each positioning cavity is connected to the mold cavity, and the mold cavity comprises a frame cavity for forming the frame, and a sealing cavity for forming the sealing structure, and the height of the sealing cavity is greater than the height of the frame cavity.

[0026] Furthermore, the upper mold is provided with a separation protrusion located above each of the supporting surfaces and convexly arranged along the circumference of the supporting surface. The separation protrusion can press the four sides of the gas diffusion plate against the supporting surface to separate the positioning cavity and the mold cavity.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The preform preparation system described in the present invention forms a positioning cavity and a mold cavity by fastening the upper mold body and the lower mold body in the injection mold. The positioning cavity is connected to the mold cavity, and the height of the frame cavity in the mold cavity is less than the height of the sealing cavity, which is beneficial to the preparation of preforms and helps improve the production efficiency of preforms.

[0029] In addition, the provision of multiple adsorption holes on the support surface facilitates adsorption of the gas diffusion sheet onto the support surface, thereby ensuring the effective positioning of the gas diffusion sheet. The provision of a partition structure within the extended portion of the frame cavity also facilitates the integrated formation of multiple flow channel holes on the frame, further improving the processing efficiency of the membrane electrode. The provision of a separation protrusion facilitates the separation of the positioning cavity from the mold cavity, thereby preventing colloid from penetrating into the interior of the gas diffusion layer and affecting its performance.

[0030] In addition, the present invention also proposes a preform, which is made using the preform preparation method as described above, and the preform includes a frame with a sealing structure and two gas diffusion plates symmetrically arranged in the frame, and the sealing structure is arranged along the circumference of at least one of the gas diffusion plates.

[0031] The prefabricated part of the present invention is manufactured by adopting the prefabricated part manufacturing method as described above, which is beneficial to improving the production efficiency of the prefabricated part and has good practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 This is a flow chart of the prefabricated component preparation method according to the first embodiment of the present invention;

[0034] Figure 2 This is a schematic structural diagram of a gas diffusion sheet according to a first embodiment of the present invention;

[0035] Figure 3 This is a schematic structural diagram of the positioning cavity and the mold cavity according to the first embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the reverse structure of the prefabricated component according to the first embodiment of the present invention;

[0037] Figure 5 This is a structural schematic diagram of the front surface of the preform and the CCM membrane according to the first embodiment of the present invention;

[0038] Figure 6 This is a schematic structural diagram of a prefabricated component according to a second embodiment of the present invention;

[0039] Figure 7This is a schematic structural diagram of the auxiliary tooling according to the third embodiment of the present invention;

[0040] Figure 8 This is a structural schematic diagram of the pressure plate described in Example 3 of the present invention.

[0041] Description of reference numerals:

[0042] 1. Gas diffusion plate; 100. Positioning cavity;

[0043] 2. Frame; 200. Mold cavity; 201. First sealing portion; 202. Flow channel hole; 203. Second sealing portion;

[0044] 3. CCM membrane;

[0045] 4. Auxiliary tooling; 401. Guide hole;

[0046] 5. Press plate; 501. Press down the protrusion. DETAILED DESCRIPTION

[0047] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0048] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Furthermore, in the description of the present invention, unless otherwise expressly defined, the terms "mounted," "connected," "connect," and "connector" should be interpreted broadly. For example, these terms may refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will appreciate the specific meanings of these terms in the present invention based on the specific circumstances.

[0050] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0051] Example 1

[0052] This embodiment relates to a method for preparing a membrane electrode preform, so as to simplify the preparation process of the membrane electrode preform and improve the production efficiency of the preform.

[0053] Overall, if Figure 1 As shown in , the preparation method of the preform comprises the following steps:

[0054] Two gas diffusion sheets 1 are symmetrically positioned in two positioning cavities 100 of the injection mold;

[0055] Colloid is injected into the periphery of the two positioning cavities 100 to form a frame 2 with a sealing structure. The two gas diffusion sheets 1 are connected together through the frame to obtain a prefabricated component.

[0056] The preform preparation method of this embodiment first positions the gas diffusion sheet 1 within the positioning cavity 100 and then injects the colloid into the mold cavity 200. This allows the frame 2 with a sealing structure to be formed on the gas diffusion layer, making it easier to obtain the preform. Compared to traditional methods of forming a sealing structure on the membrane electrode preform and bipolar plate, this method not only simplifies the membrane electrode preform preparation process but also avoids problems caused by forming a sealing structure on the membrane electrode preform and bipolar plate, thereby improving the membrane electrode qualification rate. Furthermore, the high connection strength between the colloid and the gas diffusion layer, as well as the sealing structure and the frame 2, improves the performance of the preform.

[0057] Specifically, as a preferred embodiment, the gas diffuser sheet 1 in this embodiment can be cut from carbon paper. Before symmetrically positioning the two gas diffuser sheets 1 within the two positioning cavities 100 of the injection mold, the carbon paper is cut into two identical rectangles. Of course, the shape and specifications of the gas diffuser sheet 1 can be adjusted to suit specific needs. Besides carbon paper, the gas diffuser sheet 1 can also be made from carbon cloth.

[0058] like Figure 2 and Figure 3 As shown in FIG, each positioning cavity 100 is adapted to the shape of the gas diffusion sheet 1, and the two positioning cavities 100 are spaced apart and arranged in parallel. The mold cavity 200 is adapted to the shape of the frame 2, and the mold cavity 200 is arranged along the circumference of each positioning cavity 100 and can connect the two positioning cavities 100. After the colloid is injected into the mold cavity 200 and solidifies, the edge of the gas diffusion sheet 1 is bonded to the frame 2.

[0059] As a preferred embodiment, symmetrically positioning two gas diffusion plates 1 in the positioning cavity 100 of the injection mold includes: the two gas diffusion plates 1 in the positioning cavity 100 are in the same plane, the edges of each gas diffusion plate 1 in the positioning cavity 100 extend outward to the mold cavity 200 outside the positioning cavity 100, and the above-mentioned colloid is injected into the mold cavity 200.

[0060] Here, the two gas diffusion sheets 1 are in the same plane in the positioning state, which is beneficial to improving the product performance of the preform. The edges of the gas diffusion sheets 1 extend outward into the mold cavity 200, which is beneficial to increasing the connection area between the gas diffusion sheets 1 and further improving the connection firmness between the gas diffusion sheets 1 and the frame 2.

[0061] In this embodiment, in the step of injecting colloid into the mold cavity 200 to form the frame 2 structure connecting the two gas diffusion sheets 1 together, the colloid is heated and cured after injection to form the frame 2, and the heating temperature T satisfies: 80°C ≤ T ≤ 120°C. For example, the heating temperature T can be 80°C, 90°C, 100°C, 110°C or 120 degrees Celsius. The heating temperature within this numerical range is conducive to improving the curing and molding effect of the colloid. Of course, in specific implementation, the heating temperature is set according to the characteristics of the colloid, as long as it meets the use requirements.

[0062] Preferably, the colloid in this embodiment is injection-molded silica gel or injection-molded silicone rubber, so that the molded frame 2 has better elasticity, which is not only beneficial to the folding of the preform, but also beneficial to the upper and lower layers of the frame 2 after folding to be able to adhere together due to their own properties, so as to form a sealed space between the two layers of the frame 2, thereby further improving the sealing effect of the CCM membrane 3.

[0063] The structure of the prefabricated part in this embodiment is as follows Figure 3 and Figure 4 As shown in FIG, the frame 2 has two frame parts corresponding to each gas diffusion sheet 1, and three flow channel holes 202 are formed at both ends of one frame part. For the convenience of the following description, one side of the preform is called the front side, and the other side is called the back side. Figure 4 As shown in the figure, the sealing structure in this embodiment includes a first sealing portion 201 provided on the front side of the frame 2 and protruding along the circumference of the two gas diffusion plates 1, and a plurality of second sealing portions 203 respectively provided on the front and back sides of the frame 2 and protruding along the circumference of each flow channel hole 202.

[0064] In this embodiment, during the formation of the frame 2, the first sealing portion 201 and the second sealing portion 203 are simultaneously formed on the frame 2. Simultaneously, the frame 2 is tightly connected to each gas diffusion sheet 1, resulting in improved molding efficiency and structural robustness. It should be noted that the first sealing portion 201 can also be provided only along the circumference of one gas diffusion sheet 1. In this case, the first sealing portion 201 can also meet the sealing requirements of the membrane electrode during use.

[0065] Specifically, because the gas diffuser sheet 1 has a porous structure, the colloid in the mold cavity 200 can penetrate the edges of the gas diffuser sheet 1. As the colloid solidifies, the frame 2 is tightly bonded to the edges of the two gas diffuser sheets 1. In this case, there is no need to apply glue between the gas diffuser sheet 1 and the frame 2 to increase the connection strength between the two.

[0066] Example 2

[0067] This embodiment relates to a membrane electrode preparation method, including the preform preparation method in Example 1, and further comprising: connecting the CCM membrane 3 to one of its gas diffusion sheets 1, and then folding the preform in half; compacting the preform to seal the CCM membrane 3 between the two gas diffusion sheets 1 to obtain a membrane electrode.

[0068] The CCM membrane 3 is connected to one of the gas diffusion sheets 1, and then the preform is folded in half and positioned at a preset position on a positioning tool. The positioning tool has multiple positioning columns and multiple flow channel holes 202 formed on the frame 2;

[0069] In this embodiment, Figure 5 As shown in FIG, during the step of bonding the CCM membrane 3 to one of the gas diffusion sheets 1 and then folding the preform in half, the four edges of the CCM membrane 3 are bonded to the reverse side of one of the gas diffusion sheets 1. After the preform is folded in half along the symmetry line between the two gas diffusion sheets 1, the four edges of the CCM membrane 3 are bonded to the reverse side of the other gas diffusion sheet 1. The four edges of the CCM membrane 3 are bonded to each of the gas diffusion sheets 1 via an adhesive layer, which allows the CCM membrane 3 to be sealed between the two gas diffusion sheets 1.

[0070] In specific implementation, the adhesive layer is a pressure-sensitive adhesive, which is beneficial to improving the bonding effect between the CCM membrane 3 and the two gas diffusion sheets 1. Of course, in addition to pressure-sensitive adhesive, the adhesive layer can also be other products with bonding effects.

[0071] As a preferred embodiment, the folded preform is as follows Figure 6 As shown in FIG. During the step of compacting the preform to seal the CCM membrane 3 between the two gas diffusion sheets 1, a rolling cylinder is used to press the bonding area between the CCM membrane 3 and the two gas diffusion sheets 1, thereby compacting the preform. Here, using the rolling cylinder to press the bonding area between the CCM membrane 3 and the two gas diffusion sheets 1 helps improve the sealing effect of the CCM membrane 3 between the two gas diffusion sheets 1.

[0072] Furthermore, before folding the preform in half, the preform can be positioned in a predetermined position. This step includes positioning the preform in the predetermined position by fitting the plurality of flow holes 202 onto the plurality of positioning posts. Positioning the preform in the predetermined position through the cooperation of the flow holes 202 and the positioning posts on the frame 2 is easy to implement and provides a good positioning effect. Specifically, the number of positioning posts preferably matches the number of flow holes 202 to achieve a good positioning effect.

[0073] The membrane electrode preparation method in this embodiment can facilitate the formation of the frame 2 and the sealing structure by optimizing each step, which is not only beneficial to the preparation of the membrane electrode, but also helps to improve the qualified rate of the membrane electrode preparation.

[0074] Example 3

[0075] This embodiment relates to a prefabricated component preparation system, which is used to execute the prefabricated component preparation method in the first embodiment.

[0076] In terms of overall structure, the preform preparation system in this embodiment includes an injection mold. The injection mold includes an upper mold body and a lower mold body that are fastened together. The upper mold body and the lower mold body form two positioning cavities 100 and a mold cavity 200 located outside the positioning cavities 100. Each positioning cavity 100 is connected to the mold cavity 200. The mold cavity 200 includes a frame cavity for forming the frame 2 and a sealing cavity for forming a sealing structure. The height of the sealing cavity is greater than that of the frame cavity.

[0077] The prefabricated film preparation system of this embodiment forms a positioning cavity 100 and a mold cavity 200 by fastening the upper mold body and the lower mold body in the injection mold. The positioning cavity 100 is connected to the mold cavity 200, and the height of the frame cavity in the mold cavity 200 is less than the height of the sealing cavity, which is beneficial to the preparation of prefabricated parts and helps to improve the production efficiency of prefabricated parts.

[0078] In this embodiment, both the upper and lower mold bodies are provided with cavities. When the upper and lower mold bodies are fastened together, the two cavities cooperate to form the aforementioned positioning cavity 100 and mold cavity 200. In the fastened state, the gas diffusion sheet 2 is centered in the thickness direction of the mold cavity 200, thereby ensuring that the supported membrane electrode has a better performance.

[0079] As a preferred embodiment, the frame cavity includes two sub-cavities, one corresponding to each gas diffusion sheet 1. One of the sub-cavities has an extension with outwardly projecting ends. The upper and lower mold bodies are fastened together to form a plurality of partition structures within the extensions, which are used to form flow passage holes 202. The provision of the partition structures within the extensions in the frame cavity also facilitates the integrated formation of multiple flow passage holes 202 on the frame 2, thereby further improving the processing efficiency of the preform.

[0080] Specifically, the partition structure includes three protrusions corresponding to each extension part, which are provided on one of the upper mold body and the lower mold body, and grooves provided on the other of the two for the insertion of each protrusion. By inserting the protrusions into the corresponding grooves, the colloid cannot be formed here, thereby facilitating the formation of three flow channel holes 202 on the frame 2 at both ends of one gas diffusion plate 1 on the frame 2.

[0081] As a preferred embodiment, the lower mold body in this embodiment is provided with a supporting surface for forming the bottom of the positioning cavity 100, and a plurality of adsorption holes extending through the supporting surface. The plurality of adsorption holes are connected to the external vacuum unit to adsorb the gas diffuser sheet 1. The provision of the plurality of adsorption holes on the supporting surface facilitates adsorption of the gas diffuser sheet 1 on the supporting surface, thereby ensuring the positioning of the gas diffuser sheet 1.

[0082] Further, such as Figure 7 As shown in , the injection mold in this embodiment further includes an auxiliary tooling 4 capable of being positioned on the lower mold body. Auxiliary tooling 4 has a guide hole 401 located above the support surface. Guide hole 401 is configured to conform to the shape of gas diffuser sheet 1 to guide the gas diffuser sheet 1 to its target position on the support surface. This arrangement facilitates guiding the gas diffuser sheet 1 to its target position on the support surface by conforming the guide hole 401 on the auxiliary tooling 4 to the shape of the gas diffuser sheet 1. Furthermore, the auxiliary tooling 4 has a simple structure and is easy to deploy and implement.

[0083] In addition, in this embodiment, the upper mold is provided with a separating protrusion located above each supporting surface and extending outwardly along the circumference of the supporting surface. The separating protrusion can press the periphery of the gas diffusion sheet 1 against the supporting surface, thereby separating the positioning cavity 100 from the mold cavity 200. Here, the separating protrusion facilitates separating the positioning cavity 100 from the mold cavity 200, thereby preventing colloid from penetrating into the interior of the gas diffusion layer and affecting the performance of the gas diffusion layer.

[0084] In order to improve the compaction of prefabricated parts, the prefabricated part preparation system in this embodiment further includes a pressing plate 5, such as Figure 8 As shown in , the pressing plate 5 is positioned above the folded preform, and the side of the pressing plate 5 facing the preform is provided with a downward pressing protrusion 501 corresponding to the bonding area between the CCM membrane 3 and the two gas diffusion sheets 1. The rolling cylinder mentioned in Example 1 specifically rolls on the top surface of the pressing plate 5, and presses the bonding area between the CCM membrane 3 and the two gas diffusion sheets 1 through the downward pressing protrusion 501. The provision of the downward pressing protrusion 501 further enhances the bonding strength between the CCM membrane 3 and the two gas diffusion sheets 1, thereby improving the sealing effect of the CCM membrane 3 between the two gas diffusion sheets 1.

[0085] To facilitate positioning of the preform, the preform preparation system also includes a positioning fixture having a positioning surface. In one embodiment, multiple positioning posts are provided on the positioning fixture to position the preform on the positioning surface. Furthermore, the positioning fixture may also be provided with suction holes to enhance the positioning of the preformed electrode film on the positioning surface through vacuum suction.

[0086] To prepare the prefabricated electrode membrane, two gas diffuser sheets 1 are first dropped through guide holes 401 in the auxiliary tooling 4 onto the corresponding support surface. Each gas diffuser sheet 1 is then attracted through the adsorption holes, securing it in place on the support surface. The upper and lower mold bodies are then fastened together, and glue is injected into the mold cavity 200 through the liquid inlet channel. Heat is applied until the glue solidifies, and after cooling, the prefabricated electrode membrane is completed.

[0087] The taken-out preform is positioned on the positioning surface of the positioning tool, the CCM membrane 3 is bonded to one of the gas diffusion sheets 1 , and the preform is folded in half so that the CCM membrane 3 is bonded to both gas diffusion sheets 1 .

[0088] Then, a pressing plate 5 is placed on top of the folded preform, and the pressing plate 5 is rolled by a roller. The preform is compacted by the pressing protrusion 501 on the pressing plate 5 to seal the CCM membrane 3 between the two gas diffusion sheets 1 to obtain a membrane electrode.

[0089] The preform preparation system in this embodiment has a simple structure and is easy to implement, which is conducive to realizing the membrane electrode preparation method of the first embodiment and improving the processing efficiency and qualified rate of the membrane electrode.

[0090] Example 4

[0091] This embodiment also relates to a preform, which is produced using the preform production method described in Example 1. The preform includes a frame having a sealing structure and two gas diffusion sheets 1 symmetrically disposed within the frame 2. The sealing structure is disposed along the circumference of at least one of the gas diffusion sheets 1. The preform in this embodiment is produced using the preform production method described above, which facilitates improved production efficiency and has good practicality.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a membrane electrode preform, characterized in that: The prefabricated part preparation method comprises: symmetrically positioning two gas diffusion sheets (1) in two positioning cavities (100) of an injection mold; Colloid is injected into the periphery of the two positioning cavities (100) to form a frame (2) with a sealing structure, and the two gas diffusion sheets (1) are connected together through the frame to obtain the prefabricated part.

2. The method for preparing a membrane electrode preform according to claim 1, characterized in that: The method of injecting colloid into the periphery of the two positioning cavities (100) to form a frame (2) connecting the two gas diffusion sheets (1) together comprises: After the colloid is injected, it is heated and solidified to form the frame (2), and the heating temperature T satisfies: 80°C≤T≤120°C.

3. The method for preparing a membrane electrode preform according to claim 1 or 2, characterized in that: The gas diffusion sheet (1) is carbon paper or carbon cloth, and the colloid is injection-molded silica gel or injection-molded silicone rubber.

4. A membrane electrode preparation method, characterized in that: A method for preparing a preform according to any one of claims 1 to 3; further comprising: Connecting a CCM membrane (3) to one of the gas diffusion sheets (1), and then folding the preform in half; The preform is compacted to seal the CCM membrane (3) between the two gas diffusion sheets (1) to obtain a membrane electrode.

5. The membrane electrode preparation method according to claim 4, characterized in that: The method of symmetrically positioning two gas diffusion sheets (1) in a positioning cavity (100) of an injection mold comprises: The two gas diffusion plates (1) in the positioning cavity (100) are located in the same plane; The edges of each of the gas diffusion sheets (1) in the positioning cavity (100) extend outwards into a mold cavity (200) at the periphery of the positioning cavity (100), and the colloid is injected into the mold cavity (200).

6. The membrane electrode preparation method according to claim 4, characterized in that: The step of compacting the preform to seal the CCM membrane (3) between the two gas diffusion sheets (1) comprises: The preform is compacted by rolling the bonding area between the CCM film (3) and the two gas diffusion sheets (1) using a rolling drum.

7. A prefabricated part preparation system, characterized in that: The preparation system is used to perform the preform preparation method according to any one of claims 1 to 3, and the preform preparation system comprises an injection mold; The injection mold comprises an upper mold body and a lower mold body that are fastened together, and the two positioning cavities (100) and a mold cavity (200) located on the periphery of the positioning cavity (100) are formed therebetween. Each of the positioning cavities (100) is connected to the mold cavity (200), and the mold cavity (200) comprises a frame cavity for forming the frame (2) and a sealing cavity for forming the sealing structure. The height of the sealing cavity is greater than the height of the frame cavity.

8. The preform preparation system according to claim 7, characterized in that: The lower mold body is provided with a supporting surface for forming the bottom of the positioning cavity (100), and a plurality of adsorption holes provided through the supporting surface, wherein the plurality of adsorption holes are connected to an external vacuum part to adsorb the gas diffusion sheet (1); and / or, The frame cavity comprises two sub-cavities respectively arranged corresponding to each of the gas diffusion plates (1), and one of the sub-cavities has an extension portion with two ends protruding outwards, and the upper mold body and the lower mold body are buckled together to form a plurality of partition structures located in the extension portion, and the partition structures are used to form flow channel holes (202).

9. The preform preparation system according to claim 8, characterized in that: The upper mold is provided with a separation protrusion located above each of the supporting surfaces and convexly arranged along the circumference of the supporting surface. The separation protrusion can press the four sides of the gas diffusion plate (1) against the supporting surface to separate the positioning cavity (100) and the mold cavity (200).

10. A prefabricated part, characterized in that: The preform is made by the preform preparation method according to any one of claims 1 to 3, and the preform comprises a frame having a sealing structure and two gas diffusion plates (1) symmetrically arranged in the frame (2), and the sealing structure is arranged along the circumference of at least one of the gas diffusion plates (1).

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