A fuel cell gas diffusion layer carbon paper hydrophobic device and a preparation method thereof

Abstract

The present application relates to a kind of fuel cell gas diffusion layer carbon paper hydrophobic equipment and preparation method.The present application includes hydrophobic liquid preparation system, including the water tank and preparation tank connected;Deionized water in the water tank can be transported to the preparation tank and mixed with PTFE solution in the preparation tank, to obtain hydrophobic liquid;Hydrophobic system, including carbon paper roller conveying line, impregnation module and liquid squeezing module connected in sequence;The impregnation tank is connected with preparation tank, and the hydrophobic liquid can be transported from the preparation tank to the impregnation tank;Carbon paper roller conveying line is used to transport carbon paper to the impregnation tank, to carry out carbon paper impregnation by the impregnation tank;Liquid squeezing module is used to squeeze the excess hydrophobic liquid of impregnated carbon paper;Drying system, with hydrophobic system interface, to dry the carbon paper after liquid squeezing processing.The present application can realize the continuous hydrophobic of carbon paper to meet the continuous production of fuel cell, and improve the hydrophobic uniformity of gas diffusion layer in preparation process.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a carbon paper hydrophobic device and preparation method for a fuel cell gas diffusion layer. Background Technology

[0002] The gas diffusion layer (GDL) is a key component of the membrane electrode assembly (MEA) in a proton exchange membrane fuel cell (PEM). The performance of the GDL is closely related to the performance of the MEA, which in turn directly affects the performance of the single cell. The functions of the gas diffusion layer in a fuel cell are: ① to support the catalyst layer and stabilize the electrode structure; ② to provide gas, electron, and drainage channels for the electrode reactions; ③ to transfer reactants (fuel and catalyst); and ④ to ensure conductivity between the bipolar plates and the catalyst layer. During fuel cell power generation, hydrogen oxidation occurs at the anode, producing protons and electrons. The generated electrons reach the cathode via an external circuit, while the generated protons are transferred to the cathode through the proton exchange membrane. At the cathode, oxygen gains electrons and reacts with the protons to produce water. This water needs to be rapidly discharged through the gas diffusion layer. If the gas diffusion layer cannot quickly drain the water, it will flood the catalyst layer, hindering the further progress of the reaction.

[0003] There are two existing methods for preparing gas diffusion layers. One is roll-to-roll preparation, which is suitable for large-scale mass production. The equipment is large and costly, and the hydrophobic tank and drying oven need to be long enough to meet product requirements. A production line can be tens of meters long. The other is sheet-to-sheet preparation, which involves manual mixing, manual impregnation, and manual drying. It is generally used for laboratory preparations and has low efficiency and low output. Summary of the Invention

[0004] Therefore, the present invention provides a hydrophobic device and preparation method for carbon paper in the gas diffusion layer of fuel cells, which can achieve continuous hydrophobicity of carbon paper to meet the needs of continuous fuel cell production, can achieve automatic hydrophobicity of carbon paper in the gas diffusion layer, has high working efficiency, saves manpower, and can improve the hydrophobicity uniformity of the gas diffusion layer during the preparation process.

[0005] To solve the above-mentioned technical problems, the present invention provides a carbon paper hydrophobic device for a fuel cell gas diffusion layer, comprising:

[0006] A hydrophobic liquid preparation system includes a water tank and a preparation tank connected together; deionized water in the water tank can be transported to the preparation tank and mixed with a PTFE solution in the preparation tank to obtain a hydrophobic liquid;

[0007] The hydrophobic system includes a carbon paper roller conveyor line, an impregnation module, and a liquid-pinching module connected in sequence. The impregnation module includes an impregnation tank connected to the preparation tank, and the hydrophobic liquid can be transported from the preparation tank to the impregnation tank. The carbon paper roller conveyor line is used to transport carbon paper to the impregnation tank for impregnation. The liquid-pinching module is used to extrude excess hydrophobic liquid from the impregnated carbon paper.

[0008] A drying system is connected to the hydrophobic system to dry the carbon paper after it has been spun into liquid.

[0009] In one embodiment of the present invention, a first magnetic pump and a first mass flow meter are sequentially connected between the water tank and the preparation tank, and a first diaphragm pump is connected between the preparation tank and the impregnation tank.

[0010] In one embodiment of the present invention, the preparation tank is a stirring tank, and both the preparation tank and the impregnation tank are equipped with a linear density detector.

[0011] In one embodiment of the present invention, a replenishment tank is further included, and a second magnetic pump and a second mass flow meter are connected between the replenishment tank and the preparation tank.

[0012] In one embodiment of the present invention, the impregnation tank has a waste discharge port connected to a second diaphragm pump. The impregnation tank is equipped with a cooling pipe, a liquid level sensor, a concentration sensor, and a filter. The cooling pipe is laid flat on the inner wall of the impregnation tank and connected to a chiller. The liquid level sensor and the concentration sensor are both located at the bottom center of the impregnation tank and connected to a host computer. The filter is located between the preparation tank and the impregnation tank and is connected by a pipeline.

[0013] In one embodiment of the present invention, the carbon paper roller conveying line includes a conveying roller line, which includes a single roller conveying area and an upper and lower double roller conveying area. The single roller conveying area includes multiple sets of single rollers arranged at equal intervals, and the upper and lower double roller conveying area includes multiple sets of upper and lower double rollers arranged at equal intervals. The distance between two adjacent single rollers and two adjacent upper and lower double rollers is less than the length of the carbon paper. The carbon paper is conveyed from the single roller conveying area to the upper and lower double roller conveying area and is clamped and advanced by the upper and lower double rollers. The conveying roller line includes an inlet section inclined downwards at 30-80° to the horizontal plane of the impregnation tank along its conveying direction, an impregnation section parallel to the horizontal plane of the impregnation tank, and an outlet section inclined upwards at 30-80° to the horizontal plane of the impregnation tank along its conveying direction.

[0014] In one embodiment of the present invention, anti-deviation baffles are provided on both sides of the roller conveyor line in the transverse direction, and a guide protection mesh is provided at the lower longitudinal direction. The horizontal plane of the guide protection mesh is 3-5mm lower than the tangent point of the upper and lower double rollers, so as to prevent the carbon paper from sagging due to gravity during the conveying process.

[0015] In one embodiment of the present invention, the liquid-pressing module includes a liquid-pressing roller assembly. A scraper is provided on one side of the roller surface of the liquid-pressing roller assembly, and a liquid receiving box is provided on the lower side of the liquid-pressing roller assembly. Residual solution on the liquid-pressing roller assembly is cleaned by the scraper and collected by the liquid receiving box and then returned to the impregnation tank. The liquid-pressing roller assembly includes an upper liquid-pressing roller and a lower liquid-pressing roller that rotate relative to each other. The upper liquid-pressing roller is connected to a cylinder to adjust the gap between the upper liquid-pressing roller and the lower liquid-pressing roller.

[0016] In one embodiment of the present invention, the drying system includes a tunnel-type oven, inside which is a stainless steel mesh conveyor belt. Above the stainless steel mesh conveyor belt are nozzles for blowing air. The internal temperature of the oven is controlled within the range of 20-150°C. The oven is heated by stainless steel electric heating tubes and ventilated by an exhaust fan.

[0017] This invention also provides a method for preparing a gas diffusion layer using a carbon paper hydrophobic device for fuel cell gas diffusion layers, comprising:

[0018] Deionized water from the water tank is transferred to the preparation tank and mixed with the PTFE solution in the preparation tank to obtain a hydrophobic liquid;

[0019] The hydrophobic solution is transported from the preparation tank to the impregnation tank;

[0020] Carbon paper is conveyed into the impregnation tank via a carbon paper roller conveyor line for impregnation.

[0021] The liquid-squeezing module is used to extrude excess hydrophobic liquid from the impregnated carbon paper.

[0022] After being squeezed, the carbon paper is conveyed to the drying system by the carbon paper roller conveyor line for drying.

[0023] After drying, the carbon paper is manually removed and stacked.

[0024] The technical solution of the present invention has the following advantages compared with the prior art:

[0025] This invention discloses a hydrophobic device and preparation method for carbon paper used in a fuel cell gas diffusion layer. The carbon paper is transported via a roller conveyor line, ensuring uniform stress on the paper. Furthermore, the carbon paper enters and exits the impregnation tank at a specific angle, resulting in a small contact area with the liquid surface. This reduces the surface pressure of the liquid on the carbon paper within the impregnation tank. As long as the hydrophobic tank is of sufficient length to guarantee the hydrophobic time of the carbon paper, the roller conveyor line can accelerate the conveying speed and improve production efficiency. In contrast, traditional sheet carbon paper is first cut into sheets and then manually or with tools placed one by one into the impregnation tank. This method is inefficient and the uneven stress on the carbon fibers within the paper makes it easily damaged.

[0026] The anti-deviation baffles on both sides of the rollers on the roller line of this equipment can prevent the carbon paper from deviating laterally during the transmission process and prevent the protective mesh plate in the longitudinal direction from falling below the tangent point of the upper and lower rollers by 3-5mm. This also prevents the carbon paper from sagging due to gravity during the transmission process. Firstly, it prevents the carbon paper from falling down, and secondly, it plays a guiding role, allowing the carbon paper to smoothly enter the next set of rollers.

[0027] The equipment uses steel rollers against steel rollers, and the hydrophobic load on the carbon paper is kept uniform and stable by adjusting the clamping force between the two rollers. Therefore, as long as the clamping force between the two rollers is adjusted properly, the hydrophobic load of the entire batch of carbon paper is uniform. The rollers are equipped with scrapers for regular cleaning, and the liquid receiving box pipe under the rollers is connected to the impregnation tank. Excess solution squeezed out by the steel rollers is collected through the liquid receiving box and returned to the impregnation tank, achieving a recycling effect and avoiding waste.

[0028] The drying oven of this equipment adopts an integrated tunnel design and is a main drive type drying oven. It uses a stainless steel mesh to transport carbon paper for drying. The advantage is that the drying time can be adjusted according to the transmission speed of the conveyor line, and the single sheet is easier to dry evenly. At the same time, upper and lower air knives are set at the inlet and outlet of the drying oven area, located directly above and below the carbon paper, which can accurately sweep the upper and lower surfaces of the carbon paper to remove excess carbon powder, impurities and other particles from the surface of the carbon paper.

[0029] This equipment can automatically hydrophobize the gas diffusion layer carbon paper, which has high working efficiency, saves manpower, and can improve the hydrophobic uniformity of the gas diffusion layer during the preparation process. Attached Figure Description

[0030] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the overall structure of the carbon paper hydrophobic device for the fuel cell gas diffusion layer of the present invention.

[0032] Figure 2 This is a schematic diagram of the hydrophobic liquid preparation system of the present invention.

[0033] Figure 3 This is a schematic diagram of the hydrophobic system structure of the present invention.

[0034] Figure 4 This is a schematic diagram of the carbon paper roller conveyor line structure of the present invention.

[0035] Figure 5 This is a side view of the carbon paper roller conveyor line of the present invention.

[0036] Figure 6 This is a schematic diagram of the liquid rolling module structure of the present invention.

[0037] Figure 7 This is a schematic diagram of the drying system structure of the present invention.

[0038] Explanation of reference numerals in the instruction manual:

[0039] 00. Fuel cell gas diffusion layer carbon paper hydrophobic device;

[0040] 10. Hydrophobic liquid preparation system; 11. Water tank; 12. First magnetic pump; 13. First mass flow meter; 14. First diaphragm pump; 15. Linear density meter; 16. Replenishment tank; 17. Second magnetic pump; 18. Second mass flow meter; 19. Second diaphragm pump;

[0041] 20. Hydrophobic system; 21. Preparation tank; 22. Carbon paper roller conveyor line; 22-1. Conveying roller line; 22-2. Guide protection mesh plate; 22-3. Anti-deviation baffle; 23. Impregnation module; 23-1. Impregnation tank; 23-2. Impregnation tank cover; 24. Rolling module; 24-1. Upper rolling roller; 24-2. Lower rolling roller; 24-3. Scraper; 24-4. Cylinder;

[0042] 30. Drying system; 31. Air nozzle; 32. Exhaust fan; 33. Electric heating element; 34. Stainless steel mesh conveyor belt. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0044] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0045] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0046] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0047] Reference Figure 1 As shown, a fuel cell gas diffusion layer carbon paper hydrophobic device 00 of the present invention includes:

[0048] The hydrophobic liquid preparation system 10 includes a water tank 11 and a preparation tank 21 connected together; the deionized water in the water tank 11 can be transported to the preparation tank 21 and mixed with the PTFE solution in the preparation tank 21 to obtain a hydrophobic liquid;

[0049] The hydrophobic system 20 includes a carbon paper roller conveyor line 22, an impregnation module 23, and a liquid-pinching module 24 connected in sequence. The impregnation module 23 includes an impregnation tank 23-1 and an impregnation tank cover 23-2. The impregnation tank 23-1 is connected to the preparation tank 21, and the hydrophobic liquid can be transported from the preparation tank 21 to the impregnation tank 23-1. The carbon paper roller conveyor line 22 is used to transport carbon paper to the impregnation tank 23-1 for impregnation. The liquid-pinching module 24 is used to extrude excess hydrophobic liquid from the impregnated carbon paper.

[0050] The drying system 30 is connected to the hydrophobic system 20 to dry the carbon paper after it has been spun into liquid.

[0051] In some embodiments, refer to Figure 2As shown, a first magnetic pump 12 and a first mass flow meter 13 are sequentially connected between the water tank 11 and the preparation tank 21, and a first diaphragm pump 14 is connected between the preparation tank 21 and the impregnation tank 23-1; the preparation tank 21 is a stirring tank, and both the preparation tank 21 and the impregnation tank 23-1 are equipped with a linear density detector 15; a replenishment tank 16 is also included, and a second magnetic pump 17 and a second mass flow meter 18 are connected between the replenishment tank 16 and the preparation tank 21.

[0052] In some embodiments, refer to Figure 3 As shown, the impregnation tank 23-1 has a waste discharge port connected to a second diaphragm pump 19. The impregnation tank 23-1 is equipped with a cooling pipe, a liquid level sensor, a concentration sensor, and a filter. The cooling pipe is laid flat on the inner wall of the impregnation tank 23-1 and connected to a chiller. The liquid level sensor and the concentration sensor are both located at the bottom center of the impregnation tank 23-1 and connected to a host computer. The filter is located between the preparation tank 21 and the impregnation tank 23-1 and is connected by a pipeline.

[0053] With the above setup, deionized water is calculated and delivered to preparation tank 21 via the first magnetic pump 12 and the first mass flow meter 13. PTFE solution is added to preparation tank 21 manually. Preparation tank 21 has a slow stirring function to mix the solution, and the solution density is detected by the first online density detector 15. After the hydrophobic solution is prepared, the liquid is pumped into impregnation tank 23-1 by the first diaphragm pump 14 for carbon paper impregnation. Impregnation tank 23-1 is equipped with a linear density detector 15. When the density decreases, a high-concentration hydrophobic solution is pumped into impregnation tank 23-1 by the replenishment tank 16 to adjust its density. The solution in impregnation tank 23-1 can be filtered through pipelines and the liquid is circulated back to preparation tank 21. When the system needs cleaning, the liquid in the immersion tank 23-1 is discharged through the drain port, deionized water is pumped into the water tank 11, and the deionized water is used to rinse the preparation tank 21, the replenishment tank 16, and the immersion tank 23-1 through the cleaning pipeline. Finally, the liquid is discharged through the drain port of the immersion tank 23-1, completing the automatic cleaning.

[0054] In some embodiments, refer to Figure 4As shown, the carbon paper roller conveyor line 22 includes a conveyor roller line 22-1. The roller conveyor line includes a single-roller conveying area and upper and lower double-roller conveying areas. The single-roller conveying area includes multiple sets of equally spaced single rollers, and the upper and lower double-roller conveying areas include multiple sets of equally spaced upper and lower double rollers. The distance between two adjacent single rollers and between two adjacent upper and lower double rollers is less than the length of the carbon paper. The carbon paper is conveyed from the single-roller conveying area to the upper and lower double-roller conveying area and is held forward by the upper and lower double rollers. The roller conveyor line maintains a certain angle when immersed in the hydrophobic liquid and also maintains a certain angle when exiting the immersion tank. The advantage is that the carbon paper can withstand lower water pressure, preventing damage from liquid pressure when entering and exiting the immersion tank 23-1. The conveying roller line 22-1 includes an inlet section inclined downwards at 30-80° to the horizontal plane of the impregnation tank 23-1 along its conveying direction, an impregnation section parallel to the horizontal plane of the impregnation tank 23-1, and an outlet section inclined upwards at 30-80° to the horizontal plane of the impregnation tank 23-1 along its conveying direction.

[0055] With the above setup, the carbon paper is manually placed onto a single roller. The single roller conveyor transports the carbon paper to the double roller conveyor, where the upper and lower double rollers hold the carbon paper in place. To ensure stable forward movement of the carbon paper and controllable movement in the solution, each piece of carbon paper is held by at least two sets of upper and lower double rollers simultaneously. The upper and lower double rollers act as drive wheels, squeezing the gaps in the carbon paper during the feeding process, allowing the solution to fully penetrate the carbon paper. The rollers are made of custom-designed rubber rollers, preventing the solution from entering the rollers and affecting their rotation. The rollers are also easy to disassemble and clean.

[0056] In some embodiments, refer to Figure 5 As shown, anti-deviation baffles 22-3 are provided on both sides of the roller conveyor line in the transverse direction. The width of the anti-deviation baffles 22-3 on both sides of the roller can be adjusted according to the size of the carbon paper to prevent the carbon paper from deviating in the transverse direction during the transmission process. A guide protection mesh plate 22-2 is provided at the lower longitudinal direction. The longitudinal protection mesh plate has three functions: first, to prevent the carbon paper from falling down; second, to guide the carbon paper to ensure that it moves in the predetermined direction; and third, to ensure that the carbon paper is not damaged by excessive water pressure when it is immersed in the impregnation tank 23-1. The horizontal plane of the guide protection mesh plate 22-2 is 3-5mm lower than the tangent point of the upper and lower double rollers to prevent the carbon paper from sagging due to gravity during the transmission process and failing to enter the next set of rollers.

[0057] Using a roller conveyor line to transport carbon paper ensures uniform force on the carbon paper. Furthermore, the carbon paper enters and exits the impregnation tank at a certain angle, resulting in a small contact area with the liquid surface. This reduces the surface pressure of the liquid on the carbon paper within the impregnation tank. As long as the drainage groove is of sufficient length to ensure the drainage time of the carbon paper, the roller conveyor line can accelerate the conveying speed and improve production efficiency.

[0058] In some embodiments, refer to Figure 6As shown, the liquid-pressing module 24 includes a liquid-pressing roller assembly. A scraper 24-3 is provided on one side of the roller surface of the liquid-pressing roller assembly, and a liquid receiving box is provided on the lower side of the assembly. Residual solution on the roller assembly is cleaned by the scraper 24-3 and collected by the receiving box before flowing back into the impregnation tank 23-1. The liquid-pressing roller assembly includes an upper liquid-pressing roller 24-1 and a lower liquid-pressing roller 24-2 that rotate relative to each other. The upper liquid-pressing roller 24-1 is connected to a cylinder 24-4 to adjust the gap between the upper and lower rollers. Because uniform pressure between the two roller surfaces is necessary for a more uniform and stable hydrophobic loading of the carbon paper, the machining accuracy of the liquid-pressing steel rollers must be guaranteed. The cylinder 24-4 is connected to a precision electro-proportional valve with a pressure range of 0-1 MPa and an accuracy of 0.05-0.5%. The runout accuracy of the upper and lower squeegee rollers 24-2 is 0.05-1μm.

[0059] The upper and lower rollers 24-1 and 24-2 are chrome-plated steel rollers. The carbon paper is conveyed by a roller conveyor line. The two rollers clamp the carbon paper and squeeze out excess hydrophobic liquid. The residual solution on the rollers is cleaned by a scraper 24-3. The scraper 24-3 cleans the rollers periodically, so that the excess solution squeezed out by the rollers is collected in the receiving box and returned to the impregnation tank 23-1, achieving a recycling effect and avoiding waste. The hydrophobic load of the carbon paper is kept uniform and stable by adjusting the clamping force between the two rollers. Therefore, as long as the clamping force between the two rollers is adjusted properly, the hydrophobic load of the entire batch of carbon paper is uniform.

[0060] In some embodiments, refer to Figure 7 As shown, the drying system 30 includes a tunnel-type oven with an openable side door on the operating side for easy adjustment of the product status. Inside the oven, a stainless steel mesh conveyor belt 34 is installed, and nozzles for blowing air are arranged directly above the stainless steel mesh conveyor belt. The air blowing method is from top to bottom, which helps to accelerate the drying speed of the hydrophobic liquid bottom layer. The internal temperature control range of the oven is 20-150℃, and each section of the oven has independent temperature control. The oven is heated by stainless steel electric heating tubes 33 and ventilated by exhaust fans, and the exhaust air volume is frequency-adjustable.

[0061] The drying oven of this equipment adopts an integrated tunnel design and is a main drive type drying oven. It uses a stainless steel mesh to transport carbon paper for drying. The advantage is that the drying time can be adjusted according to the transmission speed of the conveyor line, and the single sheet is easier to dry evenly. At the same time, upper and lower air knives are set at the inlet and outlet of the drying oven area, located directly above and below the carbon paper, which can accurately sweep the upper and lower surfaces of the carbon paper to remove excess carbon powder, impurities and other particles from the surface of the carbon paper.

[0062] With the above setup, after the hydrophobic liquid preparation system 10 prepares the hydrophobic liquid, it is pumped into the impregnation tank 23-1 by the first diaphragm pump 14. The carbon paper is manually placed at the loading position, and the roller conveyor line transports the carbon paper to the impregnation tank 23-1 for hydrophobication. The impregnation time is determined by the conveying speed and the length of the impregnation tank 23-1. After hydrophobication, the carbon paper passes through the liquid rolling roller and enters the drying oven conveyor line. The carbon paper is dried by blowing air from top to bottom. After the carbon paper exits the drying oven, it is collected, and the entire cycle ends.

[0063] This invention also provides a method for preparing a gas diffusion layer using a carbon paper hydrophobic device for fuel cell gas diffusion layers, comprising:

[0064] Add the prepared additives, PTFE emulsion, etc. into the preparation tank 21;

[0065] Deionized water in water tank 11 is transferred to preparation tank 21 and mixed with PTFE solution in preparation tank 21 to obtain hydrophobic liquid;

[0066] The hydrophobic liquid is transported from the preparation tank 21 to the impregnation tank 23-1. After the set liquid level is reached, the circulation pipeline in the impregnation tank 23-1 is started.

[0067] The sheet carbon paper is manually placed on the carbon paper loading position in the impregnation tank 23-1; the carbon paper is then conveyed to the water drainage position in the impregnation tank 23-1 via the carbon paper roller conveyor line 22 for water drainage treatment.

[0068] The liquid-squeezing module 24 is used to extrude excess hydrophobic liquid from the surface of the impregnated carbon paper;

[0069] After being squeezed, the carbon paper is conveyed by the carbon paper roller conveyor line 22 to the drying system 30 for drying;

[0070] After drying, the carbon paper is manually removed and stacked.

[0071] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A carbon paper hydrophobic device for a fuel cell gas diffusion layer, characterized in that, include: The hydrophobic liquid preparation system (10) includes a water tank (11) and a preparation tank (21) connected together; the deionized water in the water tank (11) can be transported to the preparation tank (21) and mixed with the PTFE solution in the preparation tank (21) to obtain a hydrophobic liquid; The hydrophobic system (20) includes a carbon paper roller conveyor line (22), an impregnation module (23), and a liquid-squeezing module (24) connected in sequence. The impregnation module (23) includes an impregnation tank (23-1), which is connected to the preparation tank (21). The hydrophobic liquid can be transported from the preparation tank (21) to the impregnation tank (23-1). The carbon paper roller conveyor line (22) is used to transport carbon paper to the impregnation tank (23-1) for impregnation. The liquid-squeezing module (24) is used to extrude excess hydrophobic liquid from the impregnated carbon paper. The drying system (30) is connected to the hydrophobic system (20) to dry the carbon paper after it has been spun into liquid; The carbon paper roller conveying line (22) includes a conveying roller line (22-1), which includes a single roller conveying area and an upper and lower double roller conveying area. The single roller conveying area includes multiple sets of single rollers arranged at equal intervals, and the upper and lower double roller conveying area includes multiple sets of upper and lower double rollers arranged at equal intervals. The distance between two adjacent single rollers and two adjacent upper and lower double rollers is less than the length of the carbon paper. The carbon paper is conveyed from the single roller conveying area to the upper and lower double roller conveying area and is held forward by the upper and lower double rollers. The conveying roller line (22-1) includes an inlet section that is inclined downwards at 30-80° to the horizontal plane of the impregnation tank (23-1) along its conveying direction, an impregnation section that is parallel to the horizontal plane of the impregnation tank (23-1), and an outlet section that is inclined upwards at 30-80° to the horizontal plane of the impregnation tank (23-1) along its conveying direction. The conveying roller line (22-1) is provided with anti-deviation baffles (22-3) on both sides in the transverse direction, and a guide protection mesh plate (22-2) is provided in the lower longitudinal direction. The horizontal plane of the guide protection mesh plate (22-2) is 3-5mm lower than the tangent point of the upper and lower double rollers to avoid the carbon paper from sagging due to gravity during the conveying process.

2. The fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1, characterized in that, A first magnetic pump (12) and a first mass flow meter (13) are connected sequentially between the water tank (11) and the preparation tank (21), and a first diaphragm pump (14) is connected between the preparation tank (21) and the impregnation tank (23-1).

3. The fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1, characterized in that, The preparation tank (21) is a stirring tank, and both the preparation tank (21) and the impregnation tank (23-1) are equipped with a linear density detector (15).

4. A fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1 or 3, characterized in that, It also includes a replenishment tank (16), and a second magnetic pump (17) and a second mass flow meter (18) are connected between the replenishment tank (16) and the preparation tank (21).

5. The fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1, characterized in that, The impregnation tank (23-1) has a waste discharge port and the waste discharge port is connected to a second diaphragm pump (19). The impregnation tank (23-1) is equipped with a cooling pipe, a liquid level sensor, a concentration sensor, and a filter. The cooling pipe is laid flat on the inner wall of the impregnation tank (23-1) and connected to a chiller. The liquid level sensor and the concentration sensor are both located in the middle of the bottom of the impregnation tank (23-1) and connected to a host computer. The filter is located between the preparation tank (21) and the impregnation tank (23-1) and is connected by a pipeline.

6. The fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1, characterized in that, The liquid-pressing module (24) includes a liquid-pressing roller assembly. A scraper (24-3) is provided on one side of the roller surface of the liquid-pressing roller assembly. A liquid receiving box is provided on the lower side of the liquid-pressing roller assembly. The residual solution on the liquid-pressing roller assembly is cleaned by the scraper (24-3) and collected by the liquid receiving box and then returned to the impregnation tank (23-1). The liquid-pressing roller assembly includes an upper liquid-pressing roller (24-1) and a lower liquid-pressing roller (24-2) that rotate relative to each other. The upper liquid-pressing roller (24-1) is connected to a cylinder (24-4) to adjust the gap between the upper liquid-pressing roller (24-1) and the lower liquid-pressing roller (24-2).

7. The fuel cell gas diffusion layer carbon paper hydrophobic device according to claim 1, characterized in that, The drying system (30) includes a tunnel oven, inside which is a stainless steel mesh conveyor belt (34), and above the stainless steel mesh conveyor belt (34) are nozzles for blowing air. The internal temperature of the oven is controlled within the range of 20-150°C. The oven is heated by stainless steel electric heating tubes (33) and ventilated by exhaust fans.

8. A method for preparing a gas diffusion layer using the device according to any one of claims 1-7, characterized in that, include: Deionized water in water tank (11) is transferred to preparation tank (21) and mixed with PTFE solution in preparation tank (21) to obtain hydrophobic liquid; The hydrophobic liquid is transported from the preparation tank (21) to the impregnation tank (23-1); Carbon paper is conveyed to the impregnation tank (23-1) through the carbon paper roller conveyor line (22) for impregnation in the impregnation tank (23-1); Excess hydrophobic liquid is squeezed out from the impregnated carbon paper through the liquid-squeezing module (24); After being squeezed, the carbon paper is conveyed by the carbon paper roller conveyor line (22) to the drying system (30) for drying; After drying, the carbon paper is manually removed and stacked.

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