Fuel cell module integrated gluing process of membrane electrode based on double-sided gluing

Abstract

The invention relates to a fuel cell module integrated gluing process based on a double-sided gluing membrane electrode, which comprises the following steps: step S100, selecting a plurality of qualified frames to process into a membrane electrode, and treating the surfaces of the frames; s200, selecting a part of the treated graphite partition plates as graphite anode plates, and simultaneously selecting a part of the treated graphite partition plates as graphite cathode plates; and S300, uniformly arranging a bonding layer on each of the upper surface and the lower surface of the frame of the membrane electrode. According to the invention, the positive / negative plate and the membrane electrode form the battery cell module by adopting a hot-press gluing mode, so that a bonding layer and a solid hot melt adhesive are promoted to generate a chemical crosslinking reaction and a physical bonding effect under the hot-press action, a large-area and high-compactness connection interface is formed, the air tightness between the graphite partition plate and the membrane electrode is ensured, and the battery cell module is more compact. The precision control and the product qualification rate in the large-scale production process are remarkably improved, and the problem that the overall performance and the service life of a galvanic pile are affected due to air leakage of the cell module is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to an integrated gluing process for fuel cell modules based on double-sided glue-coated membrane electrodes. Background Art

[0002] Fuel cell stacks are mainly composed of two core components, namely bipolar plates and membrane electrodes. At present, bipolar plates account for a large proportion of fuel cells, accounting for about 80% of the total weight, 50%-65% of the volume, and 35%-40% of the total cost; it can be seen that bipolar plates, as one of the key components in fuel cells, have a significant impact on the performance and cost of fuel cells. The membrane electrode, as another core component in the fuel cell, is mainly composed of three key parts: the catalyst layer, the proton exchange membrane and the gas diffusion layer. It is the real place where the electrochemical reaction occurs inside the fuel cell. The performance of the membrane electrode directly affects the overall performance of the fuel cell, including power density, efficiency, stability and life.

[0003] The current battery stack assembly technology usually adopts a method of stacking bipolar plates and membrane electrodes alternately in sequence. For example, a 120-kilowatt battery stack requires about 300 to 400 battery cells; this means that in order to manufacture a 120-kilowatt battery stack, 600 to 800 bipolar plates and membrane electrodes must be stacked one at a time and continuously with high precision, which is a heavy burden on assembly accuracy, mold specifications, equipment specifications, and process time and labor costs.

[0004] Therefore, during the assembly process of the fuel cell stack, a tiny leak in any layer of the hundreds of assembled bipolar plates and membrane electrodes may lead to problems such as increased local resistance, gas leakage or coolant leakage, which will seriously affect the overall performance and life of the fuel cell stack. Therefore, in order to avoid this problem, the entire fuel cell stack must be disassembled and reassembled. This operation process not only affects the yield rate of the re-assembly, but also causes damage to the membrane electrode (MEA), the core component of the fuel cell, during the disassembly and assembly process, resulting in increased costs. Summary of the invention

[0005] The present invention provides a fuel cell module integrated gluing process based on double-sided glue-coated membrane electrodes to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: The integrated gluing process of the fuel cell module based on the double-sided adhesive-coated membrane electrode comprises the following steps: Step S100, selecting a number of qualified frames to be processed into membrane electrodes, and processing the surface of the frames; Step S200, selecting some of the processed graphite separators as graphite anode plates, and selecting some as graphite cathode plates; Step S300, uniformly disposing a layer of adhesive layer on the upper surface and lower surface of the frame of the membrane electrode; Step S400, opening a water seal groove on the upper surface of the graphite anode plate; Step S500, cleaning and drying the surface of the graphite cathode plate and the graphite anode plate after the water seal groove is opened; Step S600, filling the water seal groove of the graphite anode plate with solid hot melt adhesive, and attaching the graphite cathode plate to the upper surface of the graphite anode plate, and hot pressing them to form a bipolar plate; Step S700, disposing at least one membrane electrode between a graphite cathode plate and a graphite anode plate, and attaching a bipolar plate between every two adjacent membrane electrodes; Step S800, setting the time, pressure and temperature for the hot pressing equipment so that after the hot pressing operation is set, the graphite anode plate, the membrane electrode and the graphite cathode plate or the graphite anode plate, the membrane electrode, the bipolar plate and the graphite cathode plate are integrated and glued together.

[0007] Preferably, the material of the adhesive layer in step S300 is EPDM rubber, silicone rubber, fluororubber, polyolefin rubber, nitrile rubber or chloroprene rubber.

[0008] Preferably, the thickness of the adhesive layer in step S300 is 10-100 μm.

[0009] Preferably, the processing process of the frame surface in step S100 is to roughen the frame surface by frosting.

[0010] Preferably, the surface cleaning process of the graphite anode plate and the graphite cathode plate in step S500 is water washing to initially remove impurities, ultrasonic deep cleaning and plasma technology fine cleaning.

[0011] Preferably, the graphite anode plate and the graphite cathode plate are dried in step S500 by natural air drying or by using a drying device.

[0012] Preferably, in step S800, the bonding time of the graphite anode plate, the membrane electrode and the graphite cathode plate or the graphite anode plate, the membrane electrode, the bipolar plate and the graphite cathode plate is 5-20 min. Preferably, in step S800, the gluing temperature of the graphite anode plate, the membrane electrode and the graphite cathode plate or the graphite anode plate, the membrane electrode, the bipolar plate and the graphite cathode plate is 100-190°C.

[0013] Preferably, in step S800, the gluing pressure of the graphite anode plate, the membrane electrode and the graphite cathode plate or the graphite anode plate, the membrane electrode, the bipolar plate and the graphite cathode plate is 30 KN.

[0014] Preferably, in step S800, after the hot pressing process, the solid hot melt adhesive forms a sealing ring in the water sealing groove.

[0015] By adopting the above technical solution, the beneficial effects achieved by the present invention are: In the present invention, by arranging an adhesive layer on both sides of the membrane electrode and filling a fixed hot melt adhesive in the water seal groove of the graphite anode plate, the graphite anode plate, the membrane electrode, the bipolar plate and the graphite cathode plate can be integrated and glued into a battery cell module when they are assembled corresponding to each other, which greatly simplifies the production process. At the same time, the anode / cathode plate and the membrane electrode are formed into a battery cell module by hot pressing and gluing, which promotes the chemical cross-linking reaction and physical bonding effect of the adhesive layer and the solid hot melt adhesive under the action of hot pressing to form a large-area, high-density connection interface, thereby ensuring the airtightness between the graphite separator and the membrane electrode, significantly improving the precision control and product qualification rate in the large-scale production process, and avoiding the leakage of the battery cell module and affecting the overall performance and life of the battery stack.

[0016] In the present invention, a single-cell or multiple-cell battery cell module is prepared by integrating an adhesive layer and a hot-melt adhesive into a molding process, thereby successfully simplifying the complexity of the traditional battery stack assembly process, while also improving the production speed and adaptability, avoiding the problem of air leakage that is prone to occur during multi-layer assembly, improving the overall performance and life of the battery stack, and reducing the requirements for mold and equipment specifications, thereby saving process time and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of stacking the graphite anode plate, membrane electrode and graphite cathode plate of the present invention; Figure 2 It is a schematic diagram of stacking the graphite anode plate, membrane electrode, bipolar plate and graphite cathode plate of the present invention; Figure 3 It is a schematic diagram of the integrated gluing process of the single membrane electrode and the graphite separator of the present invention; Figure 4 It is a schematic diagram of the integrated gluing process of the multi-membrane electrode and the graphite separator of the present invention.

[0018] In the figure: 1. membrane electrode; 2. adhesive layer; 3. graphite anode plate; 4. graphite cathode plate; 5. solid hot melt adhesive; 6. bipolar plate. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure. Example

[0021] like Figure 1 and Figure 3 As shown, the present invention provides a fuel cell module integrated gluing process based on double-sided glue-coated membrane electrode, comprising the following steps: Step S100, selecting a number of qualified frames to be processed into membrane electrodes 1, and processing the surface of the frames; Specifically, the processing process of the frame surface is to roughen the frame surface by frosting, so that the roughened frame surface is used to increase the contact area and adhesion between the adhesive layer 2 and the graphite separator.

[0022] Step S200, selecting a portion of the processed graphite separator plates as graphite anode plates 3, and simultaneously selecting a portion as graphite cathode plates 4; Specifically, the graphite separator is mainly made of graphite material and a flexible graphite composite material formed by a hot pressing process, and the material has a porous structure, which is conducive to being closely connected with the bonding material during the hot pressing process.

[0023] Step S300, uniformly disposing a layer of adhesive layer 2 on the upper surface and lower surface of the frame of the membrane electrode 1; Specifically, the material of the bonding layer 2 is EPDM rubber, silicone rubber, fluororubber, polyolefin rubber, nitrile rubber or chloroprene rubber. A series of rubber materials with excellent bonding properties and chemical resistance are selected by using the bonding layer 2 material, so that the bonding layer 2 serves as a key link in connecting the membrane electrode 1 with the graphite anode plate 3 and the graphite cathode plate 4, which ensures the stability of the graphite anode plate 3, the membrane electrode 1 and the graphite cathode plate 4 after connection.

[0024] Furthermore, the thickness of the adhesive layer 2 is 10-100 μm.

[0025] The thickness of the adhesive layer 2 is 10-100 μm, which can ensure that the membrane electrode 1 has sufficient bonding strength with the graphite anode plate 3 and the graphite cathode plate 4, while avoiding the problem of excessive volume or increased cost due to excessive thickness.

[0026] Step S400, opening a water seal groove on the upper surface of the graphite anode plate 3; Step S500, cleaning and drying the graphite cathode plate 4 and the graphite anode plate 3 after the water seal groove is opened; Specifically, the surface cleaning process of the graphite anode plate 3 and the graphite cathode plate 4 is water washing to initially remove impurities, ultrasonic deep cleaning and plasma technology fine cleaning, and the drying treatment of the graphite anode plate 3 and the graphite cathode plate 4 is natural air drying or drying treatment using drying equipment; It should be noted that the specific cleaning can be flexibly set according to the characteristics and cleaning requirements of the graphite anode plate 3 and the graphite cathode plate 4. The specific operation method is well known to those skilled in the art and will not be described in detail herein. Step S600, filling the water seal groove of the graphite anode plate 3 with solid hot melt adhesive 5; Specifically, an anode reaction area is provided on the front side of the graphite anode plate 3, and a cathode reaction area is provided on the front side of the graphite cathode plate 4, and the two reaction areas are arranged correspondingly so as to realize an effective chemical reaction in the battery. In order to ensure the normal operation and safety of the battery, the back side of the graphite anode plate 3 and the back side of the graphite cathode plate 4 are glued together by solid hot melt adhesive 5. After the hot pressing process, the solid hot melt adhesive 5 will form a sealing ring in the water seal groove, which can effectively prevent the leakage of the coolant and provide stable structural support.

[0027] As a further preference, the graphite anode plate 3 and the graphite cathode plate 4 are glued together, and a coolant flow channel is formed between the two. The function of the coolant flow channel is to effectively conduct the heat generated by the battery to keep the temperature of the battery within an appropriate range. This structure is a well-known and disclosed technology in the art and has been mastered by those skilled in the art. This solution will not elaborate on this in detail.

[0028] Furthermore, when the solid hot melt adhesive 5 is filled in the water seal groove, its end surface part protrudes from the water seal groove, and this design ensures that the solid hot melt adhesive 5 can effectively prevent the leakage of the coolant, and the depth of the water seal groove can be adjusted according to actual needs, generally set in the range of 0.3-1.0mm, and the thickness of the solid hot melt adhesive 5 can be selected in the range of 0.3-10mm to meet the sealing and cooling requirements under different working conditions; Step S700, placing a single membrane electrode 1 between the graphite cathode plate 4 and the graphite anode plate 3; Step S800, setting the time, pressure and temperature for the hot pressing equipment so that after the hot pressing operation is set, the graphite anode plate 3, the membrane electrode 1 and the graphite cathode plate 4 are integrated and glued together.

[0029] Specifically, when a single membrane electrode 1 is placed between a graphite anode plate 3 and a graphite cathode plate 4, it forms a single battery cell module after hot pressing, wherein the gluing time of the graphite anode plate 3, the membrane electrode 1 and the graphite cathode plate 4 is 5-20 minutes, the gluing temperature is 100-190°C, and the gluing pressure is 30KN.

[0030] Furthermore, when forming a single battery cell module, one side of the membrane electrode 1 is bonded to the graphite anode plate 3 through the adhesive layer 2, and the other side of the membrane electrode 1 is bonded to the graphite cathode plate 4 through the adhesive layer 2, so that the graphite anode plate 3, the membrane electrode 1 and the graphite cathode plate 4 are integrated and bonded by hot pressing. This process not only ensures the close fit and efficient conductivity between the component materials, but also enhances the stability and durability of the overall structure, while also greatly simplifying the manufacturing process, which not only saves time and resources, but also reduces process complexity, thereby improving production efficiency and quality control level.

[0031] Furthermore, when assembling a fuel cell stack based on an integrated glued single-cell module, it is first necessary to conduct a strict airtightness test on the glued single-cell module. Only qualified modules that pass the test can enter the stack assembly stage. This rigorous quality control method eliminates potential defective products, greatly improves the yield rate of the stack assembly, meets the urgent needs of large-scale production for high quality and high yield rate, and provides strong support for efficient mass production and market promotion. Example

[0032] like Figure 2 and Figure 4 As shown, the present invention provides a fuel cell module integrated gluing process based on double-sided glue-coated membrane electrode, comprising the following steps: Step S100, selecting a number of qualified frames to be processed into membrane electrodes 1, and processing the surface of the frames; Step S200, selecting a portion of the processed graphite separator plates as graphite anode plates 3, and simultaneously selecting a portion as graphite cathode plates 4; Step S300, uniformly disposing a layer of adhesive layer 2 on the upper surface and lower surface of the frame of the membrane electrode 1; Specifically, the material of the adhesive layer 2 is EPDM rubber, silicone rubber, fluororubber, polyolefin rubber, nitrile rubber or chloroprene rubber. The adhesive layer 2 is made of a series of rubber materials with excellent bonding properties and chemical resistance, so that the adhesive layer 2 serves as a key link in connecting the membrane electrode 1 with the graphite anode plate 3 and the graphite cathode plate 4, and ensures the stability of the graphite anode plate 3, the membrane electrode 1 and the graphite cathode plate 4 after connection; Furthermore, the thickness of the adhesive layer 2 is 10-100 μm.

[0033] The thickness of the adhesive layer 2 is 10-100 μm, which can ensure that the membrane electrode 1 has sufficient bonding strength with the graphite anode plate 3 and the graphite cathode plate 4, while avoiding the problem of excessive volume or increased cost due to excessive thickness; Step S400, opening a water seal groove on the upper surface of the graphite anode plate 3; Step S500, cleaning and drying the graphite cathode plate 4 and the graphite anode plate 3 after the water seal groove is opened; Specifically, the surface cleaning process of the graphite anode plate 3 and the graphite cathode plate 4 is water washing to initially remove impurities, ultrasonic deep cleaning and plasma technology fine cleaning, while the drying treatment of the graphite anode plate 3 and the graphite cathode plate 4 adopts natural air drying or drying treatment using drying equipment.

[0034] Step S600, filling the water seal groove of the graphite anode plate 3 with solid hot melt adhesive 5, and attaching the graphite cathode plate 4 to the upper surface of the graphite anode plate 3, and hot pressing them to form a bipolar plate 6; Specifically, when the solid hot melt adhesive 5 is filled in the water seal groove, its end surface part protrudes from the water seal groove. Generally, the depth range of the water seal groove is set between 0.3-1.0 mm, and the thickness of the solid hot melt adhesive 5 can be selected in the range of 0.3-10 mm, so that when the graphite anode plate 3 and the graphite cathode plate 4 are in the gluing mold, the solid hot melt adhesive 5 forms a circle of tightly fitting sealing ring in the water seal groove on the graphite anode plate 3 after hot pressing, so that the graphite anode plate 3 and the graphite cathode plate 4 are glued together through the sealing ring to form the bipolar plate 6, and this sealing ring makes the bipolar plate 6 have excellent waterproofness and durability, and can maintain stable performance in extreme working environments; Step S700, disposing at least two membrane electrode 1 between the graphite cathode plate 4 and the graphite anode plate 3, and simultaneously attaching the bipolar plate 6 between every two adjacent membrane electrode 1; Step S800, setting the time, pressure and temperature for the hot pressing equipment so that after the hot pressing operation is set, the graphite anode plate 3, the membrane electrode 1, the bipolar plate 6 and the graphite cathode plate 4 are integrated and glued together.

[0035] Specifically, when multiple membrane electrodes 1 are placed between the graphite anode plate 3 and the graphite cathode plate 4, multiple bipolar plates 6 can be simultaneously placed between every two membrane electrodes 1 to form a multi-cell module after hot pressing, wherein the gluing time of the graphite anode plate 3, the membrane electrode 1, the bipolar plate 6 and the graphite cathode plate 4 is 5-20 min, the gluing temperature is 100-190°C, and the gluing pressure is 30KN.

[0036] Furthermore, when forming a multi-cell module, one side of the graphite anode plate 3 is bonded to the membrane electrode 1 through the adhesive layer 2, one side of the graphite cathode plate 4 is bonded to the membrane electrode 1 through the adhesive layer 2, and both sides of the bipolar plate 6 are bonded to the membrane electrode 1 through the adhesive layer 2 on the membrane electrode 1, so that the graphite anode plate 3, the membrane electrode 1, the bipolar plate 6 and the graphite cathode plate 4 are integrated and glued by hot pressing in a stacking order. This process not only ensures the close fit and efficient conductivity between the component materials, but also enhances the stability and durability of the overall structure.

[0037] Furthermore, when assembling a fuel cell stack based on the two-in-one glued multi-cell module, it is first necessary to conduct a strict airtightness test on the glued multi-cell module. Only qualified modules that pass the test can enter the stack assembly stage. This rigorous quality control method eliminates potential defective products, greatly improves the yield rate of the stack assembly, meets the urgent needs of large-scale production for high quality and high yield rate, and provides strong support for efficient mass production and market promotion.

[0038] As a further preferred embodiment, the processing process of the frame surface in step S100 is to roughen the frame surface by frosting, and this processing process is the same as the processing process in the above-mentioned embodiment 1.

[0039] As a further preference, in the step S800 , the solid hot melt adhesive 5 forms a sealing ring in the water seal groove after the hot pressing process. It should be noted that the solid hot melt adhesive 5 here is the solid hot melt adhesive 5 in the water seal groove on a single graphite anode plate 3 .

[0040] In combination with Example 1 and Example 2, when assembling a battery stack for a single-cell module or a multi-cell module, there is no need to rely on a high-precision mechanical positioning arm during the assembly process, and a simpler horizontal stacking method can be adopted. Therefore, this assembly method, combined with the unique process flow design in this solution, significantly reduces the complexity of the battery stack assembly and improves the overall qualification rate of the product, which is very suitable for the actual needs of large-scale battery stack production. The above-mentioned simple horizontal stacking method is a well-known public technology and has been well known and applied by technical personnel in this field. This article will not elaborate on this.

[0041] Furthermore, since the assembled battery stack is carried out through an integrated battery cell module, the battery stack obtained by this method is later repairable. The repair method is to take out the broken battery cell module and replace it with a new one. And since the modules are in contact with each other through the cooling water flow channel, the membrane electrode 1 will not be damaged during the replacement of the battery cell module. At the same time, since the requirements for mold and equipment specifications are reduced, the production cost can be reduced and the market competitiveness of the product can be improved.

[0042] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A fuel cell module integrated gluing process based on double-sided adhesive-coated membrane electrode, characterized in that: The following steps are involved: Step S100, selecting a number of qualified frames to be processed into membrane electrodes (1), and processing the surface of the frames; Step S200, selecting a portion of the processed graphite separator plates as graphite anode plates (3), and simultaneously selecting a portion as graphite cathode plates (4); Step S300, uniformly disposing a layer of adhesive layer (2) on the upper surface and lower surface of the frame of the membrane electrode (1); Step S400, opening a water seal groove on the upper surface of the graphite anode plate (3); Step S500, cleaning and drying the surface of the graphite cathode plate (4) and the graphite anode plate (3) after the water seal groove is opened; Step S600, filling the water seal groove of the graphite anode plate (3) with solid hot melt adhesive (5), and attaching the graphite cathode plate (4) to the upper surface of the graphite anode plate (3), and hot pressing them to form a bipolar plate (6); Step S700, arranging at least one membrane electrode (1) between a graphite cathode plate (4) and a graphite anode plate (3), and laminating a bipolar plate (6) between every two adjacent membrane electrodes (1); Step S800, setting the time, pressure and temperature of the hot pressing equipment so that after the hot pressing operation is set, the graphite anode plate (3), the membrane electrode (1) and the graphite cathode plate (4) or the graphite anode plate (3), the membrane electrode (1), the bipolar plate (6) and the graphite cathode plate (4) are integrated and glued together.

2. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1 is characterized in that: The material of the adhesive layer (2) in step S300 is EPDM rubber, silicone rubber, fluororubber, polyolefin rubber, nitrile rubber or chloroprene rubber.

3. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 2 is characterized in that: The thickness of the adhesive layer (2) in step S300 is 10-100 μm.

4. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1 is characterized in that: The processing process of the frame surface in step S100 is to roughen the frame surface by frosting.

5. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: The surface cleaning process of the graphite anode plate (3) and the graphite cathode plate (4) in step S500 includes water washing to initially remove impurities, ultrasonic deep cleaning, and plasma technology fine cleaning.

6. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: In step S500, the graphite anode plate (3) and the graphite cathode plate (4) are dried by natural air drying or by using a drying device.

7. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: In step S800, the gluing time of the graphite anode plate (3), the membrane electrode (1) and the graphite cathode plate (4) or the graphite anode plate (3), the membrane electrode (1), the bipolar plate (6) and the graphite cathode plate (4) is 5-20 minutes.

8. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: In step S800, the gluing temperature of the graphite anode plate (3), the membrane electrode (1) and the graphite cathode plate (4) or the graphite anode plate (3), the membrane electrode (1), the bipolar plate (6) and the graphite cathode plate (4) is 100-190°C.

9. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: In step S800, the bonding pressure of the graphite anode plate (3), the membrane electrode (1) and the graphite cathode plate (4) or the graphite anode plate (3), the membrane electrode (1), the bipolar plate (6) and the graphite cathode plate (4) is 30 KN.

10. The integrated gluing process for fuel cell modules based on double-sided adhesive-coated membrane electrodes according to claim 1, characterized in that: In step S800, after the hot pressing process, the solid hot melt adhesive (5) forms a sealing ring in the water seal groove.

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