Square alkaline water electrolytic bath membrane pad integrated structure and production process thereof

Abstract

The invention discloses a square alkaline water electrolyzer membrane pad integrated structure and a production process thereof.The square alkaline water electrolyzer membrane pad integrated structure comprises a square rubber gasket and a PPS composite membrane, the square rubber gasket is arranged on the periphery of the PPS composite membrane in a wrapping mode and is vulcanized and formed into the integrated structure, and during vulcanization, an adhesive tape is matched with a mold for integrated vulcanization; when no stainless steel wire exists in the membrane-pad integrated structure, the mold is amplified by 2% according to the requirement for the shrinkage rate of rubber, overall preparation is firstly carried out, finally, the membrane-pad integrated structure is placed in a steam channel to shrink the PPS composite membrane, and when the stainless steel wire exists in the membrane-pad integrated structure, the shrinkage rate of the rubber is reduced to 0.2%, and the mold is amplified according to the shrinkage rate of 0.2%; the method comprises the following steps: preshrinking the PPS composite diaphragm, and then integrally preparing. The sealing function can be effectively kept, meanwhile, mounting and dismounting of the square electrolytic cell are facilitated, the purity of gas is guaranteed, the overall performance of the square electrolytic cell is improved, the preparation efficiency is high, and the quality is good.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a square alkaline water electrolyzer membrane pad integrated structure and a production process thereof. Background Art

[0002] As a zero-carbon emission energy, hydrogen energy is regarded as an ideal choice for sustainable development. At present, water electrolysis hydrogen production technology has become the main way to obtain green hydrogen and is of significant importance. Among the various methods of water electrolysis hydrogen production, alkaline water electrolysis hydrogen production technology has achieved industrial production and has the conditions for large-scale application. It is a mature and reliable hydrogen production process. Its core equipment, the alkaline water electrolyzer, plays a vital role in the entire hydrogen production process. The square electrolyzer has huge advantages in saving manufacturing costs, modular combination of unit cells, and lower working pressure.

[0003] Since alkaline water electrolyzers are usually assembled from pole frames, the seal between pole frames is the key to ensure the normal operation of the electrolyzer. As an important component for achieving sealing, the sealing gasket affects the safety of the electrolyzer. The assembly form of the sealing gasket and the diaphragm of the traditional circular electrolyzer is that the diaphragm gasket is stacked, that is, the diaphragm is stacked on the surface of the sealing gasket. This assembly method is inconvenient for installation and disassembly, and it is easy for the diaphragm to curl inward due to uneven force when the electrolyzer is compressed. Long-term operation may cause hydrogen and oxygen to cross each other and reduce the purity of hydrogen. The assembly method of the square electrolyzer is a modular assembly of unit cells in the horizontal direction. The independent structure of the diaphragm and the sealing gasket of the traditional circular electrolyzer is not conducive to the assembly of the square electrolyzer, and it is easy for the edge of the diaphragm to separate from the sealing gasket, resulting in poor sealing and low safety of the electrolyzer.

[0004] Therefore, it is urgent to develop an integrated diaphragm gasket structure to meet the requirements of square alkaline water electrolyzers for sealing and hydrogen purity. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a square alkaline water electrolyzer membrane pad integrated structure and its production process. The present invention can effectively maintain the sealing function, while facilitating the installation and disassembly of the square electrolyzer, ensuring the purity of the gas, improving the overall performance of the square electrolyzer, and having high preparation efficiency and good quality.

[0006] In order to solve the above technical problems, the present invention provides a square alkaline water electrolyzer membrane gasket integrated structure, including a square rubber gasket and a PPS composite diaphragm, wherein the square rubber gasket is coated on the periphery of the PPS composite diaphragm and vulcanized into an integrated structure.

[0007] Furthermore, edge sealing lines are arranged on the peripheries of the two surfaces of the square rubber gasket, a middle sealing line is arranged on the surface of the square rubber gasket within the edge sealing line, a cross sealing line is arranged at the junction of the middle sealing lines between two adjacent edges of the square rubber gasket, matching flow channel holes are arranged on the square rubber gasket and the PPS composite diaphragm, and an annular sealing line is arranged on the square rubber gasket around the flow channel hole.

[0008] Furthermore, a plurality of annular steel wire rings arranged from the inside to the outside are arranged inside the square rubber gasket.

[0009] A production process for a membrane-gasket integrated structure, used for preparing a membrane-gasket integrated structure without stainless steel wire, wherein the square rubber gasket is made of EPDM rubber;

[0010] The following steps are involved:

[0011] Step 1) enlarging and manufacturing an upper mold and a lower mold according to the design size of the integrated membrane pad and the 2% shrinkage rate of the EPDM rubber after cooling, and the upper mold and the lower mold are not provided with bosses corresponding to the flow channel holes;

[0012] Step 2) preforming a rubber blank of EPDM rubber with a rubber preforming machine, and cutting the rubber blank into rubber strips with the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips and a second layer of rubber strips, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to the two lengths and two widths of the square rubber gasket respectively;

[0013] Step 3) Place the first layer of adhesive strips into the long side and wide side of the lower mold, and then cover the first layer of adhesive strips with a layer of high-temperature anti-sticking cloth, and then continue to lay the second layer of adhesive strips on the high-temperature anti-sticking cloth, and the position of the second layer of adhesive strips corresponds to that of the first layer of adhesive strips;

[0014] Step 4) The upper mold and the lower mold are molded together for initial low-temperature vulcanization, the overflowed waste rubber is removed, the high-temperature anti-sticking cloth is removed, and the PPS composite diaphragm is laid between the first layer of rubber strips and the second layer of rubber strips to ensure that the PPS composite diaphragm is laid flat to prevent wrinkles; the molds are pressed together again for secondary vulcanization to obtain a vulcanized membrane pad integrated structure blank, the membrane pad integrated structure blank is trimmed, and it is placed at room temperature to cool and shrink;

[0015] Step 5) placing the cooled film-pad integrated structure blank into a steam channel to pre-shrink the PPS composite diaphragm to obtain a pre-shrinked film-pad integrated structure;

[0016] Step 6) punching out flow channel holes on the pre-shrunk film-pad integrated structure to obtain a finished film-pad integrated structure.

[0017] Furthermore, the hardness of the EPDM rubber is Shore 75A, the length and width of the PPS composite diaphragm are smaller than the outer circumference of the square rubber gasket and larger than the inner circumference of the rubber gasket, and the thermal deformation temperature of the PPS composite diaphragm under a load of 1.8 MPa is 265°C.

[0018] Furthermore, the time of the initial low-temperature vulcanization is 5-10 seconds; the vulcanization temperature of the secondary vulcanization is 150-170°C, and the vulcanization time is 40-50 minutes; and the temperature of the steam channel is 200°C.

[0019] Furthermore, the size of the high-temperature anti-sticking cloth is larger than the outer circumference size of the upper mold and the lower mold.

[0020] A production process of a membrane-gasket integrated structure, used for preparing a membrane-gasket integrated structure with stainless steel wire, wherein the square rubber gasket is made of EPDM rubber; the process comprises the following steps:

[0021] Step 1) pre-shrinking the PPS composite diaphragm through a steam channel;

[0022] Step 2) According to the design size of the membrane pad and the setting of a plurality of annular wire rings arranged from the inside to the outside, the EPDM rubber is enlarged by 0.2% shrinkage rate and the upper mold and the lower mold are made according to the above size, and the upper mold and the lower mold are located at the position corresponding to the flow channel hole. Bosses are set;

[0023] Step 3) preforming a rubber blank from EPDM rubber using a rubber preforming machine, and cutting the rubber blank into rubber strips having the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips and a second layer of rubber strips, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to the two lengths and two widths of the square rubber gasket, respectively;

[0024] Step 4) multiple stainless steel wires with a diameter of 1 mm are arranged at the same interval, and adjacent stainless steel wires are transversely connected and welded into an annular wire ring, and the annular wire ring is provided with an avoidance hole at a position corresponding to the flow channel hole;

[0025] Step 5) firstly put the first layer of rubber strips into the long side and the wide side of the lower mold, then lay the annular wire ring on the first layer of rubber strips, the avoidance hole of the annular wire ring corresponds to the boss on the lower mold, then lay the pre-shrunk PPS composite diaphragm on the annular wire ring to ensure that the PPS composite diaphragm is in a flat and wrinkle-free state, and finally lay the second layer of rubber strips on the PPS composite diaphragm and correspond to the position of the first layer of rubber strips;

[0026] Step 6) The upper mold and the lower mold are pressed together for vulcanization to obtain a vulcanized membrane pad integrated structure blank, the membrane pad integrated blank is trimmed to remove excess flash, and is placed at room temperature to cool and shrink, thereby obtaining a membrane pad integrated structure that can be used for a square alkaline water electrolyzer.

[0027] Furthermore, the length and width of the annular steel wire ring match the length and width of the membrane gasket; the stainless steel wire on one side of the annular steel wire ring evenly covers the width of one side of the rubber gasket without leaking out.

[0028] Furthermore, after placing the annular wire ring, the shrinkage rate of the EPDM rubber was reduced to 0.2%.

[0029] Furthermore, in step 6, the temperature of the mold closing and pressurizing is between 150-170° C., and the vulcanization time is 40-50 minutes.

[0030] Beneficial effects of the present invention:

[0031] 1. The present invention provides an integrated diaphragm gasket structure for a square alkaline water electrolyzer, wherein EPDM rubber is selected as the main body of the square rubber gasket, and a PPS composite diaphragm is vulcanized in the middle of the square rubber gasket to achieve integrated molding of the diaphragm and the sealing gasket, while maintaining the sealing function and facilitating the installation and disassembly of the square electrolyzer, thereby ensuring the purity of the gas and improving the overall performance of the square electrolyzer.

[0032] 2. The present invention provides an integrated diaphragm gasket structure for a square alkaline water electrolyzer. Sealing lines are arranged on both side surfaces of the rubber gasket and around the flow channel holes to enhance the sealing performance. At the same time, the pre-tightening force required for the electrolyzer is reduced to a certain extent to achieve the requirement of 20% compression of the rubber gasket when the electrolyzer is in working condition.

[0033] 3. In the production process of the integrated structure of the diaphragm gasket without stainless steel wire provided by the present invention, the manufactured membrane gasket is light in weight and the position and size of the flow channel holes are precise.

[0034] 4. In the production process of the integrated structure of the diaphragm gasket with stainless steel wire provided by the present invention, the production process is simple, the shrinkage rate of the square rubber gasket produced is extremely small, and the diaphragm is flatter and wrinkle-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 It is a schematic diagram of the sealing line structure of the present invention;

[0037] Figure 3 It is a schematic cross-sectional view of the integrated structure of the membrane pad without the annular wire ring of the present invention;

[0038] Figure 4 It is a schematic cross-sectional view of the integrated structure of the membrane pad with an annular wire ring of the present invention;

[0039] Figure 5 It is a schematic diagram of the structure of the ring-shaped wire ring and the sealing wire of the present invention;

[0040] Figure 6 It is a schematic cross-sectional view of a part of the structure of a mold used in the first production process of the present invention;

[0041] Figure 7 It is a schematic cross-sectional diagram of a partial structure of a mold used in the second production process of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0043] Reference Figures 1 to 3 As shown, an embodiment of the square alkaline water electrolyzer membrane gasket integrated structure of the present invention includes a square rubber gasket 1 and a PPS composite diaphragm 2. The square rubber gasket is coated on the periphery of the PPS composite diaphragm and vulcanized to form an integrated structure. The integrated structure of the membrane gasket has the function of maintaining the PPS composite diaphragm and the square rubber gasket, while facilitating the installation and removal of the square electrolyzer, without the need for separate assembly of each piece, and has a good sealing effect, thereby ensuring the purity of the gas and improving the overall performance of the square electrolyzer.

[0044] Edge sealing lines 3 are also provided on the periphery of the two surfaces of the square rubber gasket, a middle sealing line 4 is provided on the surface of the square rubber gasket within the edge sealing line, and a cross sealing line 5 is provided at the junction of the middle sealing lines between two adjacent sides of the square rubber gasket to ensure the sealing of the electrolytic cell on both sides of the square rubber gasket, and matching flow channel holes 6 are provided on the square rubber gasket and the PPS composite diaphragm for the liquid to flow through, and an annular sealing line 7 is provided on the square rubber gasket around the flow channel hole to further enhance the sealing effect. At the same time, the preload force of the electrolytic cell is reduced to a certain extent.

[0045] For the above-mentioned production process of the membrane-gasket integrated structure, the square rubber gasket is used to prepare the membrane-gasket integrated structure without stainless steel wire. The square rubber gasket adopts EPDM rubber with a hardness of 75A on Shore A. EPDM rubber has the following advantages: (1) good mechanical properties and resilience; (2) alkali resistance and oxidation resistance; (3) good insulation performance; (4) can remain stable for a long time under a high temperature environment of 90°C; specifically, a PPS composite diaphragm that has not been pre-shrunk by a steam channel is used, and its length and width are smaller than the outer dimensions of the square rubber gasket and larger than the inner dimensions of the square rubber gasket. The position of the flow channel hole on the PPS composite diaphragm coincides with that on the square rubber gasket. The performance of the adopted PPS composite diaphragm: the heat deformation temperature under a load of 1.8MPa is 265°C.

[0046] The following steps are involved:

[0047] First, according to the design size of the membrane pad and the 2% shrinkage rate of the EPDM rubber after cooling, the upper mold 9 and the lower mold 10 are enlarged and made according to the above size. The upper mold and the lower mold do not have a boss corresponding to the flow channel hole. Figure 6 As shown;

[0048] Using a rubber preforming machine to preform a rubber blank from EPDM rubber, and cutting the rubber blank into rubber strips with the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips 12 and a second layer of rubber strips 13, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to the two lengths and two widths of the square rubber gasket respectively;

[0049] Put the first layer of rubber strips into the long side and wide side of the lower mold, and then cover the first layer of rubber strips with a layer of high-temperature anti-stick cloth. The size of the high-temperature anti-stick cloth is larger than the size of the mold to prevent the first layer of rubber strips from adhering to the second layer of rubber strips. Then continue to lay the second layer of rubber strips on the high-temperature anti-stick cloth and keep it in the same position as the first layer of rubber strips.

[0050] Subsequently, the upper mold and the lower mold are closed for the initial low-temperature vulcanization. The temperature of the initial vulcanization is between 120-130°C. The mold is opened after 5-10 seconds to remove the waste rubber material overflowed after the low-temperature vulcanization. The first layer of rubber strip is located in the lower mold after the initial vulcanization, while the second layer of rubber strip is in the upper mold. After the mold is opened, the second layer of rubber strip will not fall off, nor will it adhere to the high-temperature anti-sticking cloth. At this time, the high-temperature anti-sticking cloth is removed, and the PPS composite diaphragm is laid between the first layer of rubber strip and the second layer of rubber strip, that is, the PPS composite diaphragm is laid on the surface of the first layer of rubber strip to ensure that the PPS composite diaphragm is laid flat to prevent wrinkles; the mold is closed again and pressurized for secondary vulcanization. The temperature of the secondary vulcanization is 150-170°C and the vulcanization time is 40-50 minutes; after this mold opening, a vulcanized membrane pad integrated structure blank can be obtained, the membrane pad integrated structure blank is trimmed, and it is placed at room temperature to cool and shrink;

[0051] The shrinkage of the square rubber gasket and the PPS composite diaphragm of the membrane gasket is inconsistent. After the square rubber gasket shrinks by 2%, the PPS composite diaphragm will be wrinkled and uneven. The cooled membrane gasket integrated structure blank is placed in the steam channel to pre-shrink the PPS composite diaphragm. The temperature of the steam channel is 190-210℃ to ensure that the diaphragm has no wrinkles and a flat surface, so as to obtain a pre-shrunk membrane gasket integrated structure.

[0052] Finally, flow channel holes are punched out on the pre-shrunk membrane pad integrated structure to ensure that the position and size of the flow channel holes are consistent with the design requirements, thereby obtaining a finished membrane pad integrated structure, that is, a membrane pad integrated structure that can be used in a square alkaline water electrolyzer.

[0053] This method is suitable for continuous production. After the preparation of the first membrane pad integrated structure is completed, the second piece can be prepared immediately. During the preparation, since the upper mold and the lower mold need to perform the initial low-temperature vulcanization on the first and second layers of rubber strips that have just been placed, the initial low-temperature vulcanization temperature does not need to be heated again during the continuous production process. Instead, the first and second layers of rubber strips are vulcanized using the residual temperature of the upper and lower molds. At this time, the time is appropriately shortened according to the residual temperature, generally 1-5 seconds.

[0054] In this method, the PPS composite diaphragm is placed during the second vulcanization, and some waste rubber has been removed from the first and second rubber strips during the first vulcanization. During the second vulcanization, the PPS composite diaphragm will not be displaced due to overflowing rubber, and the quality is greatly improved.

[0055] In one embodiment, referring to Figure 4 and Figure 5 As shown, another embodiment of the integrated structure of the square alkaline water electrolyzer membrane pad of the present invention is based on the integrated structure of the membrane pad in the above embodiment, and a plurality of annular steel wire rings 8 arranged from the inside to the outside are arranged inside the square rubber gasket. The square rubber gasket is an integrated structure formed by welding stainless steel wires evenly arranged from the inside to the outside. At the position where the annular steel wire ring is located corresponding to the flow channel hole, an avoidance hole needs to be opened, and the size of the avoidance hole is 3-5mm larger than the avoidance hole size to avoid exposed stainless steel wire at the flow channel hole.

[0056] Specifically, the annular wire ring uses multiple stainless steel wires with a diameter of 1mm arranged at the same interval and stainless steel wires for connection are placed in the horizontal direction, and finally welded into a whole. For example, taking the square rubber gasket with a single side width of 100mm as an example, 22 sealing lines with a height of 0.5mm are set on the single side surface, including edge sealing lines and middle sealing lines, and each sealing line is 4mm apart. The main body thickness of the membrane pad integrated structure is 5mm, and the total thickness after adding the sealing lines on both sides is 6mm, among which 11 steel wires are set, and each steel wire is 8mm apart. The annular wire ring can be used to suppress the cooling shrinkage of EPDM rubber, greatly reduce the shrinkage of the rubber gasket, and ensure that the PPS composite diaphragm is flat and wrinkle-free after the membrane pad is integrally formed.

[0057] A production process for a membrane-gasket integrated structure is provided for preparing the above structure, which is used to prepare a membrane-gasket integrated structure with stainless steel wire. The square rubber gasket is made of EPDM rubber; the hardness is Shore 75A. EPDM rubber has the following advantages: (1) good mechanical properties and resilience; (2) alkali resistance and oxidation resistance; (3) good insulation performance; (4) can remain stable for a long time in a high temperature environment of 90°C. In this process, a PPS composite diaphragm that has been pre-shrunk by a steam channel is used, and its length and width are smaller than the outer dimensions of the square rubber gasket and larger than the inner dimensions of the square rubber gasket. The PPS composite diaphragm is pre-set with flow channel holes. The performance of the PPS composite diaphragm used: the heat deformation temperature under a load of 1.8MPa is 265°C.

[0058] The production process includes the following steps:

[0059] First, the PPS composite diaphragm is pre-shrunk through a steam channel, the temperature of the steam channel is 190-210°C, and the PPS composite diaphragm is in a contracted state;

[0060] Then, according to the design size of the membrane pad and the setting of a number of annular wire rings arranged from the inside to the outside, the EPDM rubber is enlarged by 0.2% and the upper mold and the lower mold are made according to the above size. The upper mold and the lower mold are located at the position corresponding to the flow channel hole to set the boss 111 to shape the flow channel hole during the vulcanization process. Figure 7 As shown;

[0061] A rubber preforming machine is used to preform a rubber blank from EPDM rubber, and the rubber blank is cut into rubber strips with the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips and a second layer of rubber strips, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to two lengths and two widths of the square rubber gasket respectively;

[0062] Arrange multiple stainless steel wires with a diameter of 1 mm at the same interval, connect adjacent stainless steel wires horizontally and weld them into annular wire rings. The annular wire rings are provided with avoidance holes at the positions corresponding to the flow channel holes to avoid the stainless steel wires from being exposed and causing interference during mold closing.

[0063] Then, place the first layer of rubber strips into the long side and wide side of the lower mold, and then lay an annular wire ring on the first layer of rubber strips, with the avoidance hole of the annular wire ring corresponding to the boss on the lower mold, and then lay the pre-shrunk PPS composite diaphragm on the annular wire ring to ensure that the PPS composite diaphragm is in a flat and wrinkle-free state, and finally lay the second layer of rubber strips on the PPS composite diaphragm and correspond to the position of the first layer of rubber strips;

[0064] Finally, the upper mold and the lower mold are closed and pressurized for vulcanization. The temperature of the mold closing and pressurization is between 150-170°C and the vulcanization time is 40-50 minutes. After the end, the mold is opened to obtain a vulcanized membrane pad integrated structure blank. The membrane pad integrated blank is trimmed to remove excess flash, and is placed at room temperature to cool and shrink, thereby obtaining a membrane pad integrated structure that can be used for a square alkaline water electrolyzer.

[0065] The present invention can be prepared by vulcanization once, with high preparation efficiency, and no need to punch out the flow channel hole later, ensuring the quality of one-piece molding. The annular wire ring is placed inside the rubber gasket, which greatly reduces the shrinkage rate of the rubber during cooling, and can make the size of the rubber gasket meet the design size requirements after cooling, ensuring that the PPS diaphragm is flat and wrinkle-free, and reducing the pre-shrinkage process of the PPS composite diaphragm after the membrane gasket is integrally formed, which is convenient for mass production.

[0066] The diaphragm gasket integrated structure provided by the present invention can be applied to square alkaline water electrolyzers. The square alkaline water electrolyzer experimental test shows that the diaphragm gasket integrated structure can be applied to square alkaline water electrolyzers at a current density of 3500A / m 2 Under the conditions of electrolytic cell temperature of 85℃ and system pressure of 0.4MPa, the energy consumption of electrolytic cell is less than 4.3kWh / Nm 3 , the oxygen content in hydrogen is 0.01%, the hydrogen content in oxygen is 0.48%, and no electrolyte leakage was found in the electrolyzer after 100 hours of operation, and the diaphragm after use still has good compression rebound performance.

[0067] The diaphragm gasket integrated structure provided by the present invention compares the performance of the PPS composite diaphragm before vulcanization and the PPS composite diaphragm after vulcanization by the first or second production process. The air tightness and resistivity of the PPS composite diaphragm are not affected by vulcanization, and the surface flatness of the PPS composite diaphragm is guaranteed during assembly due to the integrated structure, which greatly reduces the difficulty of assembly. Compared with the traditional independent diaphragm and gasket structure, the present invention facilitates the installation and disassembly of the square electrolytic cell while maintaining the sealing function, ensuring the purity of the gas and improving the overall performance of the square electrolytic cell.

[0068] The diaphragm gasket integrated structure provided by the present invention has been tested on EPDM rubber. Under hot air aging at 100°C for 70 hours, its hardness is 74A on Shore A, its elongation at break is 300%, its tensile strength is 15.8MPa, its 100% tensile strength is 5.8MPa, its permanent deformation at break is 5%, and its volume change rate is 2% under 20% concentration of alkali solution for 24 hours. It has excellent performance.

[0069] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A square alkaline water electrolyzer membrane pad integrated structure, characterized in that: It comprises a square rubber gasket and a PPS composite diaphragm. The square rubber gasket is coated on the periphery of the PPS composite diaphragm and vulcanized to form an integrated structure.

2. The square alkaline water electrolyzer membrane pad integrated structure according to claim 1, characterized in that: Edge sealing lines are arranged on the peripheries of the two surfaces of the square rubber gasket, a middle sealing line is arranged on the surface of the square rubber gasket within the edge sealing line, a cross sealing line is arranged at the junction of the middle sealing lines between two adjacent edges of the square rubber gasket, matching flow channel holes are arranged on the square rubber gasket and the PPS composite diaphragm, and an annular sealing line is arranged on the square rubber gasket around the flow channel hole.

3. The square alkaline water electrolyzer membrane pad integrated structure as claimed in claim 2, characterized in that: A plurality of annular steel wire rings arranged from the inside to the outside are arranged inside the square rubber gasket.

4. A production process of a membrane-pad integrated structure, characterized in that: For preparing the membrane-pad integrated structure described in claim 1 or 2, the square rubber gasket is made of EPDM rubber; The following steps are involved: Step 1) enlarging and manufacturing an upper mold and a lower mold according to the design size of the integrated membrane pad and the 2% shrinkage rate of the EPDM rubber after cooling, and the upper mold and the lower mold are not provided with bosses corresponding to the flow channel holes; Step 2) preforming a rubber blank of EPDM rubber with a rubber preforming machine, and cutting the rubber blank into rubber strips with the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips and a second layer of rubber strips, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to the two lengths and two widths of the square rubber gasket respectively; Step 3) Place the first layer of adhesive strips into the long side and wide side of the lower mold, and then cover the first layer of adhesive strips with a layer of high-temperature anti-sticking cloth, and then continue to lay the second layer of adhesive strips on the high-temperature anti-sticking cloth, and the position of the second layer of adhesive strips corresponds to that of the first layer of adhesive strips; Step 4) The upper mold and the lower mold are molded together for initial low-temperature vulcanization, the overflowed waste rubber is removed, the high-temperature anti-sticking cloth is removed, and the PPS composite diaphragm is laid between the first layer of rubber strips and the second layer of rubber strips to ensure that the PPS composite diaphragm is laid flat to prevent wrinkles; the molds are pressed together again for secondary vulcanization to obtain a vulcanized membrane pad integrated structure blank, the membrane pad integrated structure blank is trimmed, and it is placed at room temperature to cool and shrink; Step 5) placing the cooled film-pad integrated structure blank into a steam channel to pre-shrink the PPS composite diaphragm to obtain a pre-shrinked film-pad integrated structure; Step 6) punching out flow channel holes on the pre-shrunk film-pad integrated structure to obtain a finished film-pad integrated structure.

5. The production process of the membrane-pad integrated structure according to claim 4, characterized in that: The hardness of the EPDM rubber is Shore 75A, the length and width of the PPS composite diaphragm are smaller than the outer circumference of the square rubber gasket and larger than the inner circumference of the rubber gasket, and the thermal deformation temperature of the PPS composite diaphragm under a load of 1.8 MPa is 265°C.

6. The production process of the membrane-pad integrated structure according to claim 4, characterized in that: The time for the initial low-temperature vulcanization is 5-10 seconds; the vulcanization temperature for the secondary vulcanization is 150-170°C, and the vulcanization time is 40-50 minutes; the temperature of the steam channel is 200°C.

7. The production process of the membrane-pad integrated structure according to claim 1, characterized in that: The size of the high-temperature anti-sticking cloth is larger than the outer circumference size of the upper mold and the lower mold.

8. A production process of a membrane-pad integrated structure, characterized in that: For preparing the membrane-pad integrated structure described in claim 3, the square rubber gasket is made of EPDM rubber; The following steps are involved: Step 1) pre-shrinking the PPS composite diaphragm through a steam channel; Step 2) According to the design size of the membrane pad and the setting of a plurality of annular wire rings arranged from the inside to the outside, the EPDM rubber is enlarged by 0.2% shrinkage rate and the upper mold and the lower mold are made according to the above size, and the upper mold and the lower mold are located at the position corresponding to the flow channel hole. Bosses are set; Step 3) preforming a rubber blank from EPDM rubber using a rubber preforming machine, and cutting the rubber blank into rubber strips having the same design width as the membrane gasket; the rubber strips are divided into a first layer of rubber strips and a second layer of rubber strips, and the first layer of rubber strips and the second layer of rubber strips each have four rubber strips, and the four rubber strips correspond to the two lengths and two widths of the square rubber gasket, respectively; Step 4) multiple stainless steel wires with a diameter of 1 mm are arranged at the same interval, and adjacent stainless steel wires are transversely connected and welded into an annular wire ring, and the annular wire ring is provided with an avoidance hole at a position corresponding to the flow channel hole; Step 5) firstly put the first layer of rubber strips into the long side and the wide side of the lower mold, then lay the annular wire ring on the first layer of rubber strips, the avoidance hole of the annular wire ring corresponds to the boss on the lower mold, then lay the pre-shrunk PPS composite diaphragm on the annular wire ring to ensure that the PPS composite diaphragm is in a flat and wrinkle-free state, and finally lay the second layer of rubber strips on the PPS composite diaphragm and correspond to the position of the first layer of rubber strips; Step 6) The upper mold and the lower mold are pressed together for vulcanization to obtain a vulcanized membrane pad integrated structure blank, the membrane pad integrated blank is trimmed to remove excess flash, and is placed at room temperature to cool and shrink, thereby obtaining a membrane pad integrated structure that can be used for a square alkaline water electrolyzer.

9. The production process of the membrane-pad integrated structure according to claim 8, characterized in that: The length and width of the annular steel wire ring match the length and width of the membrane pad; the stainless steel wire on one side of the annular steel wire ring evenly covers the width of one side of the rubber gasket without leaking out.

10. The production process of the membrane-pad integrated structure according to claim 8, characterized in that: In step 6, the temperature of mold closing and pressurizing is between 150-170° C., and the vulcanization time is 40-50 minutes.

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