Gas diffusion layer with slotted hole structure and optimization and preparation method thereof

Abstract

The invention discloses a gas diffusion layer with a slotted hole structure and an optimization and preparation method thereof. A plurality of rows of slotted holes are formed in the gas diffusion layer, adjacent rows of slotted holes are arranged in a staggered manner, and each row of slotted holes is used for connecting adjacent runners in the flow field plate. The optimization method comprises the following steps: positioning and determining an initial layout of slotted holes in a gas diffusion layer according to a flow channel layout of a flow field plate; the structural parameters of the groove holes are adjusted, then numerical simulation is conducted on the battery, an output performance curve of the battery is obtained, and the structural parameters comprise the interval, the number, the width and the inclination angle of the groove holes; and comparing the output performance of the battery before and after adjustment, and screening out the structure parameter corresponding to the highest performance. The size position of the groove hole structure is highly fit with the position and layout of the flow channel, the adjacent flow channels are connected, and transverse convection can be generated by utilizing pressure drop to strengthen the output performance of the battery.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen fuel cells, and more particularly, to a gas diffusion layer with a slot hole structure and its optimization and preparation methods. Background Art

[0002] A proton exchange membrane fuel cell (referred to as PEMFC) is a power generation device that directly converts chemical energy into electrical energy through an electrochemical reaction. Due to its advantages such as high specific power, fast startup, and good environmental characteristics, it has broad application prospects in the fields of automobiles and portable electronic devices and has become one of the most promising candidates for the next-generation power source. However, limited by factors such as high fuel cell cost and poor durability and stability, it is still very difficult to promote its commercial application.

[0003] Increasing the peak power density per unit volume of the battery can reduce the size of the stack and thus reduce costs. However, at high current densities, the oxygen reduction reaction will generate a large amount of water, which will occupy the pores and block the transport path of gas reactants (this phenomenon is the well-known flooding problem), thus significantly deteriorating the output performance and life of the PEMFC. Currently, the flow field plate that bears the gas transport and drainage functions of the fuel cell has problems such as local mass transfer and drainage "dead zones" or excessive parasitic power of the pressure drop due to its inherent defects in traditional design, which is one of the main factors limiting the comprehensive output performance of the battery. Although advanced flow field designs have been continuously proposed, most of them have problems such as high manufacturing costs and difficulty in promoting mass production.

[0004] Research and development of advanced porous structures of gas diffusion layers to improve the water removal and mass transfer capabilities of the battery is another important direction in fuel cell technology research. Many studies have shown that processing groove and through-hole structures (collectively referred to as slot hole structures) in the diffusion layer can provide additional gas or liquid water transport channels for the diffusion layer.

[0005] A fuel cell gas diffusion layer with grooves and its processing method proposed in Chinese invention patent publication CN113178590A has a plurality of elliptical groove microstructures with different depths and spacings distributed on the surface of the gas diffusion layer close to the bipolar plate side; the groove spacing in the cathode inlet direction is greater than that in the outlet direction, and the groove depth in the inlet direction is less than that in the outlet direction. This makes it easier to drain the liquid water on the surface of the gas diffusion layer. However, this scheme only considers the influencing factors in the radial direction of a single flow channel to adjust the slot hole structure parameters and does not consider the influence of the entire flow field on the internal material distribution of the diffusion layer, especially the influence of the pressure difference between adjacent flow channels. Therefore, its application has limitations.

[0006] A gas diffusion layer, its preparation method and a fuel cell proposed in the Chinese invention patent publication CN117423846A include a composite carbon fiber layer, a carbon powder microporous layer and a gas channel structure. The gas diffusion layer forms a gradient pore structure, and at the same time, a plurality of grooves are provided on the surface of the first carbon fiber layer to form gas flow channels. On the basis that the gradient pore structure is helpful for drainage, the lateral transmission of water and the lateral diffusion of gas by the groove structure are utilized, which is beneficial to improving the intake air uniformity. However, the process of this diffusion layer is complex and the processing cost is high. At the same time, due to process limitations, it is difficult to design and adjust its groove structure, and it cannot flexibly adapt to various different fuel cell flow field layouts. Summary of the Invention

[0007] In order to at least solve one of the deficiencies existing in the prior art, the present invention provides a gas diffusion layer with a slot hole structure, its optimization and preparation method. The size and position of the slot hole structure highly fit the position and layout of the flow channel. The slot holes connect adjacent flow channels, and the lateral convection generated by the pressure drop can be utilized to enhance the battery output performance. The gas diffusion layer with a slot hole structure can improve different flow field defects. By setting slot holes at local positions to form mass transfer and drainage channels, the output performance and stability of the battery under high power density can be improved.

[0008] To achieve the object of the present invention, the present invention provides a gas diffusion layer with a slot hole structure. A plurality of rows of slot holes are provided on the gas diffusion layer, and the slot holes in adjacent rows are arranged in a staggered manner. Each row of slot holes is used to connect adjacent flow channels in the flow field plate.

[0009] Further, the shape of the slot hole is rectangular or parallelogram.

[0010] Further, after the gas diffusion layer and the flow field plate are finally assembled into a battery, the included angle formed between the length direction of the slot hole and the flow channels of the flow field plate is between 45° and 90°, and the slot hole passes through the rib of the flow field plate to connect adjacent flow channels on the flow field plate.

[0011] Further, the depth of the slot hole is the same as the thickness of the gas diffusion layer; the length of the slot hole is equal to the distance between the edges of two adjacent flow channels in the flow channel plate; the porous substrate of the gas diffusion layer is formed between any adjacent slot holes, forming a ridge structure, and the ridge width is equal to the spacing of the slot holes.

[0012] Further, the width of the slot hole is 0.2 mm - 0.6 mm, the depth is 0.2 mm - 0.3 mm, and the length of the slot hole = 2 * flow channel width + 1 * rib width.

[0013] Further, multiple rows of slot holes are arranged in parallel, and the central axis of each slot hole passes through the middle position between two slot holes in the adjacent row. This layout can ensure that the gas diffusion layer has a high mechanical strength.

[0014] The slot holes are parallel to each other, and the slot holes in different rows are arranged in a staggered manner.

[0015] Furthermore, the gas diffusion layer is first combined with a sealing frame made of a CCM membrane and a PET membrane to form a membrane electrode. The membrane electrode achieves a positioning relationship with the flow field plate through the sealing frame, completing the positioning between the slot holes and the flow channels.

[0016] The slot hole structure is optimized in terms of structural parameters and precisely encapsulated, and its position fits the position and layout of the flow channels, connecting adjacent flow channels.

[0017] An optimization method for the slot hole structure in a gas diffusion layer provided by the present invention includes the following steps:

[0018] Locate and determine the initial layout of the slot holes in the gas diffusion layer according to the flow channel layout of the flow field plate;

[0019] Adjust the structural parameters of the slot holes, and then perform numerical simulation on the battery to obtain the output performance curve of the battery. Among them, the structural parameters include the spacing, quantity, width, and inclination angle of the slot holes;

[0020] Compare the output performance of the battery before and after adjustment, and screen out the structural parameters corresponding to the highest performance.

[0021] When designing the slot hole structure, combine simulation to optimize parameters such as the width, spacing, position, and inclination angle of the slot hole array, and form customized porous mass transfer and drainage channels for the defects of different flow field layouts.

[0022] Furthermore, during optimization, the slot holes in the gas diffusion layer are arranged close to the corners of the flow channels.

[0023] Furthermore, the flow channel layout of the flow field plate is any one of a parallel flow field layout, a serpentine flow field layout, and an interdigitated flow field layout. Adjust the structural parameters of the slot holes through simulation and experiments to obtain a porous auxiliary channel for drainage and mass transfer that fits the flow channel layout.

[0024] Furthermore, during optimization, the slot holes in the gas diffusion layer are arranged close to the corners of the flow channels.

[0025] This optimization method optimizes the structural parameters of the slot holes for different flow field layouts. By adjusting the structural parameters such as the width, spacing, quantity, and inclination angle of the slot holes, the gas diffusion layer can make up for the design defects of different flow field layouts such as parallel, serpentine, and interdigitated flow fields. The slot holes on the gas diffusion layer provide an easily processed porous auxiliary flow channel for the flow field. It can improve the drainage ability of the parallel flow field battery, improve the uniformity and stability of the distribution of reactants at the electrode; it can reduce the pressure drop of the serpentine flow field and prevent the accumulation of liquid water at the corners; it can reduce the pressure drop of the interdigitated flow field and reduce the probability of damage to the diffusion layer during long-term operation.

[0026] Furthermore, in the parallel flow field layout, by adjusting the slot hole structure parameters, the slot holes connect the oxygen-rich and water-deficient area flow channels and the middle oxygen-deficient and water-flooded flow channels to achieve the purpose of drainage and enhanced mass transfer.

[0027] Furthermore, in the serpentine flow field layout, the slot holes connect adjacent flow channels, reducing the pressure drop between adjacent flow channels and improving the flow uniformity. The slot holes are close to the flow channel corners, thereby increasing the gas flow velocity in this area and preventing liquid water from accumulating near the flow channel corners.

[0028] Furthermore, in the interdigitated flow field layout, the slot holes connect the inlet and outlet channels, reducing the gas flow rate in the porous area of the gas diffusion layer, thereby reducing the pressure drop and preventing damage to the gas diffusion layer structure.

[0029] The present invention also provides a method for preparing a gas diffusion layer with a slot hole structure. After determining the structure parameters of the slot holes in the gas diffusion layer by the aforementioned optimization method, the gas diffusion layer is prepared. The preparation method includes the following steps:

[0030] Laser processing the gas diffusion layer in a laser device using a pre-drawn filling pattern and laser parameters;

[0031] After processing, soak it in a solution for hydrophobic treatment, take it out and dry it, and then perform heat treatment.

[0032] The rectangular or parallelogram-shaped hydrophobic slot hole structure on the diffusion layer is manufactured by a laser ablation process and a hydrophobic treatment process.

[0033] Furthermore, the laser ablation process parameters include: the laser processing speed is 50 mm / s - 200 mm / s, the processing current is 1 - 8 A, and the processing current is 5 - 8 A. The filling line spacing of the filling pattern is 0.01 mm.

[0034] Furthermore, the solution is a 5% PTFE solution or an FEP solution.

[0035] The advantages of the present invention compared with the existing diffusion layer slot hole design and manufacturing technology are as follows:

[0036] 1. The manufacturing method is simple and practical. The present invention can realize the processing and manufacturing of the diffusion layer slot hole structure by a simple laser ablation hole-opening process, and can adapt to various different slot hole size structures, with strong process applicability.

[0037] 2. The drainage and mass transfer performance of the diffusion layer is stronger. By customizing the design of the slot hole positions and sizes for the flow field layout, and using the gas convection effect between the flow channels to strengthen the lateral mass transfer between the battery flow channels, the optimized slot hole design is more conducive to improving the output power and stability of the battery under high power density.

[0038] 3. The design method has strong applicability. It specifically solves different problems existing in the diffusion layer under different flow field layout scenarios, and can provide solutions to problems such as local flooding, insufficient durability, uneven pressure distribution, and water accumulation in the flow channels within the diffusion layer.

[0039] In the prior art, the design and research and development of the diffusion layer and the flow field plate are independent of each other. The present invention enables the structure of the gas diffusion layer to adapt to the structure of the flow field plate for cross-component optimization, that is, a customized gas diffusion layer can be designed according to different application scenarios, which is innovative and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the assembly of the gas diffusion layer and the partial enlarged axonometric view inside the fuel cell in the embodiment of the present invention. Among them: 1 and 2 are slot holes in different rows, 3 is the fuel cell flow channel forming an angle with the slot holes, 6 is the gas diffusion layer with slot holes, 8 is the fuel cell flow field plate, and 9 are the assembly and positioning holes on the battery flow field plate.

[0041] Figure 2 It is a sample diagram of the gas diffusion layer after laser ablation perforation and hydrophobic treatment in the embodiment of the present invention.

[0042] Figure 3 It is an exploded view of the positioning and assembly among the gas diffusion layer, the sealing frame, and the flow field plate in the embodiment of the present invention. The exchange membrane, the catalytic layer, the gas diffusion layer, and the sealing frame together form the membrane electrode, and the structures of the exchange membrane and the catalytic layer are hidden here.

[0043] Figure 4 It is an exploded view of the assembly of the complete fuel cell single cell in the embodiment of the present invention. The battery adopts a "five-in-one" layout, and from the outside to the inside are the anode and cathode flow field plates, the anode and cathode sealing frames, and the membrane electrode with a diffusion layer in turn.

[0044] Figure 5 It is a schematic diagram of the three-dimensional contour scanning of a single slot hole in the embodiment of the present invention.

[0045] Figure 6 It is a schematic diagram of the process method of the slot hole structure combined with numerical simulation design in the embodiment of the present invention.

[0046] Figure 7 It is a streamline diagram of the local slot hole area extracted from the complete three-dimensional two-phase flow battery simulation in the embodiment of the present invention. The upper figure is the top view angle, and the lower figure is the side view angle. Among them: 11 is the slot hole area, and 12 is the porous ridge structure in the diffusion layer.

[0047] Figure 8This is a top view schematic diagram of the customized diffusion layer for a parallel flow field and its basic layout pattern of slots in an embodiment of the present invention, where: 1 is the diffusion layer slot, 2-1 is the flow field gas inlet, 2-2 is the flow field gas outlet, 3-1 is the inlet gas main channel, 3-2 is the outlet gas main channel, 4 is the branch channel, and 5 is the flow field plate rib.

[0048] Figure 9 This is a top view schematic diagram of the customized diffusion layer for a parallel flow field and its basic layout pattern of inclined slots in an embodiment of the present invention, where: 1 is the diffusion layer slot, 2-1 is the flow field gas inlet, 2-2 is the flow field gas outlet, 3-1 is the inlet gas main channel, 3-2 is the outlet gas main channel, 4 is the branch channel, and 5 is the flow field plate rib.

[0049] Figure 10 This is a top view schematic diagram of the customized diffusion layer for a serpentine flow field and its basic layout pattern of slots in an embodiment of the present invention, where: 1 is the diffusion layer slot, 2-1 is the flow field gas inlet, 2-2 is the flow field gas outlet, 3 is the serpentine flow field corner, 7 is the serpentine flow field channel, and 5 is the flow field plate rib.

[0050] Figure 11 This is a top view schematic diagram of the customized diffusion layer for an interdigitated flow field and its basic layout pattern of slots in an embodiment of the present invention, where 1 is the diffusion layer slot, 2-1 is the flow field gas inlet, 2-2 is the flow field gas outlet, 3-1 is the inlet gas main channel, 3-2 is the outlet gas main channel, 4-1 and 4-2 are the interdigitated flow field branch channels, and 5 is the flow field plate rib.

[0051] Figure 12 This is a graph of the polarization curve and power density of the battery under different slot coverage areas ((Figure (a))), different spacings ((Figure (b))), and different inclination angles ((Figure (c))) in an embodiment of the present invention. Detailed implementation mode

[0052] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only specific embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangements, expressions, and numerical values of the components and steps described in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0053] The following specifically describes the examples of the present invention.

[0054] The present invention will optimize the design of the slot hole structure across components in connection with the flow field layout. The optimization method for the slot hole structure in the gas diffusion layer in the embodiments of the present invention is to adjust and optimize the structural parameters of the slot holes in the gas diffusion layer according to the determined flow channel layout of the flow field plate. The optimization steps include:

[0055] Step 1: Locate and determine the initial slot hole layout according to the flow channel layout of the flow field plate.

[0056] Step 2: Adjust the spacing of the slot holes (enlarge or reduce), and after adjustment, perform numerical simulation on the battery to obtain the output performance curve of the battery.

[0057] Step 3: Compare the output performance of the battery before and after adjustment, and screen out the slot hole spacing corresponding to the highest performance.

[0058] Step 4: Optimize the number, width, and inclination angle of the slot holes in turn according to the above steps 2 and 3 to obtain the final slot hole design in the gas diffusion layer.

[0059] The structural parameters of the slot holes will be optimized and improved through numerical simulation. For example, Figure 6 , after positioning and designing the initial slot hole layout, adjust the spacing, number, width, and inclination angle of the slot holes in turn, and compare the output performance of the battery before and after adjustment. When the battery reaches the best output performance, the parameter optimization design of the slot hole structure is completed.

[0060] For exampleFigures 1-4 After the gas diffusion layer is finally assembled with the flow field plate into a battery, the angle formed by the length direction of the slots (1, 2) and the flow channel 3 is between 45° and 90°, so as to promote good lateral mass transfer between the flow channels and connect adjacent flow channels in the flow channel plate. The slots 1 are arranged in parallel along the length direction of the gas diffusion layer, the slots in adjacent rows are staggered, and the central axis of each slot passes through the middle position of two slots in adjacent rows. This layout ensures that the gas diffusion layer has a high mechanical strength.

[0061] like Figure 3 The gas diffusion layer is first combined with a sealing frame made of a prepared CCM (Catalyst coated membrane) membrane and a PET (polyethylene terephthalate) membrane to form a membrane electrode, and then the positioning between the slot and the flow channel is achieved through the positioning relationship between the sealing frame and the flow field plate.

[0062] The structural parameters of the slots on the gas diffusion layer include width, inclination (i.e., the angle between the slots and the flow channel), spacing, and number. Figure 4 and Figures 8-11 The slot passes through the gas diffusion layer to reach the microporous layer or the catalyst layer, the width of the slot is d = 0.2mm ~ 0.6mm, the depth of the slot is equal to the thickness of the gas diffusion layer, about 0.2mm ~ 0.3mm; the length of the slot is equal to the distance between the edges of two adjacent flow channels in the corresponding flow field, that is, the slot length l = flow channel width * 2 + rib width * 1; between any adjacent slots is a porous substrate of the gas diffusion layer, forming a ridge structure, the ridge width is equal to the slot spacing, which is a = 0.6mm ~ 2mm.

[0063] In one embodiment of the present invention, through the process of three-dimensional two-phase flow full battery simulation and experimental verification of the battery, it is confirmed that the slot structure can enhance the battery transmission performance and power output performance. Figure 7 As shown in the figure, the slot structure connects the adjacent flow channels on the flow field plate, and then the convection effect caused by the pressure difference forces the gas to pass through the electrode area below the ribs on the flow field plate and bring out the liquid water inside the electrode. Figure 12 As shown, compared with a gas diffusion layer without slots, the embodiment of the present invention adds slots and adjusts the parameters such as the coverage area, inclination angle and spacing of the slots on the gas diffusion layer, which can effectively improve the output performance of the battery at high power density. Figure 6 After optimizing the structural parameters of the slots by the method shown, the peak output performance of the battery can be improved by 30%-50% under extreme working conditions (high humidification, poor flow field mass transfer performance).

[0064] Furthermore, if Figure 12As shown in the figure, for the slot with a width d = 0.4 mm, increasing the coverage area (quantity) of the slot can improve the peak output power of the battery; increasing the spacing a of the slot can enhance the efficiency of a single slot. When the spacing increases to 0.4 mm, the performance improvement is no longer obvious; increasing the inclination angle of the slot can enhance the convective effect brought by the pressure difference between adjacent flow channels and improve the battery performance.

[0065] In one embodiment of the present invention, the basic preparation steps of the gas diffusion layer include:

[0066] (1) Laser ablation process. In an infrared laser marking machine or other laser equipment, use the pre-drawn filling pattern and laser parameters to perform customized laser processing on the gas diffusion layer, and then process the required slot structure. When performing laser ablation, use mirror-polished 310S stainless steel as the gasket at the bottom to ensure the consistency of the processed samples.

[0067] (2) Immerse the gas diffusion layer with the slot structure in a 5% PTFE solution or FEP solution for hydrophobic treatment. After taking it out and drying, perform a 3-hour heat treatment in a tube furnace at 350 °C. As Figure 2 、 Figure 4 shows, the manufactured slot structure has high stability and manufacturing accuracy, and can provide reliable process conditions for structural design.

[0068] The following further explains and illustrates the optimization of the slot structure under different flow field layouts in combination with specific embodiments.

[0069] Embodiment 1

[0070] As Figure 8 、 Figure 9 shows, a parallel flow field is provided in the flow field plate. The parallel flow field includes the inlet gas main channels 3-1 and the outlet gas main channels 3-2 on both sides, and a plurality of parallel branch channels 4 located between the inlet gas main channel 3-1 and the outlet gas main channel 3-2. The inlet gas main channel 3-1 communicates with the flow field gas inlet 2-1, and the outlet gas main channel 3-2 communicates with the flow field gas outlet 2-2. In the parallel flow field, due to the limitation of the battery size, the inlet gas main channels 3-1 and the outlet gas main channels 3-2 cannot evenly distribute the fluid to each branch channel 4. The simulation results show that the gas velocity in the middle of the battery is less than that in the branch channels 4 at both ends, which will cause the problems of waterlogging and lack of gas in the middle of the battery. In the embodiment of the present invention, the adjacent branch channels 4 are connected by the slots 1, and the convective effect is generated by the pressure drop between the adjacent branch channels 4, thereby enhancing the mass transfer performance of the diffusion layer. Moreover, the slots can be set to be inclined. As Figure 9 shows, the battery output performance can be further improved by using the upstream and downstream pressure differences through the inclined slots, and more flexible slots for different flow fields are provided.

[0071] Example 2

[0072] As Figure 10 shown, in the serpentine flow field, adjacent serpentine flow field channels 7 are connected through the slot holes 1, reducing the pressure drop between adjacent serpentine flow field channels 7 and improving the flow uniformity of the upstream and downstream channels. In the serpentine flow field, the slot holes are arranged near the channel corner 3, thereby increasing the gas flow velocity in the channel corner area and preventing the accumulation of liquid water caused by condensation and pressure drop at the channel corner.

[0073] Example 3

[0074] As Figure 11 shown, in the interdigitated flow field layout, adjacent branch channels are connected through the slot holes 1, reducing the gas flow rate in the porous area of the gas diffusion layer under the rib plate 5 of the flow field plate, thereby reducing the pressure drop and preventing the damage of the gas diffusion layer structure.

[0075] In the embodiments of the present invention, an optimized design of the slot hole structure across components is carried out in connection with the flow field layout. The slot hole structure is dimensionally designed and precisely encapsulated, and its position is highly fitted to the position and layout of the flow channel to connect adjacent flow channels.

[0076] In the embodiments of the present invention, a stable and high-precision slot hole structure can be processed on the gas diffusion layer through a laser ablation process and a hydrophobic treatment. The designed slot hole diffusion layer can improve different flow field defects. By arranging slot holes at local positions to form mass transfer and drainage channels, the output performance and stability of the battery under high power density can be improved.

[0077] The protection scope of the present invention is not limited to the above embodiments. Those skilled in the art and scientific researchers can make various modifications to the present invention without departing from the scope of the present invention. If these modifications fall within the scope of the claims of the present invention and their equivalent technologies, the intention of the present invention also includes these modifications.

Claims

1. A gas diffusion layer with a slot structure, characterized in that Multiple rows of slots are provided on the gas diffusion layer, and the slots in adjacent rows are arranged in a staggered manner. Each row of slots is used to connect adjacent flow channels in the flow field plate.

2. The gas diffusion layer with a slot structure according to claim 1, characterized in that, The shape of the slots is rectangular or parallelogram.

3. A gas diffusion layer with a slot structure according to claim 1, characterized in that, After the gas diffusion layer and the flow field plate are finally assembled into a battery, the included angle formed between the length direction of the slots and the flow channels of the flow field plate is between 45° and 90°. The slots pass through the rib plates of the flow field plate to connect adjacent flow channels on the flow field plate.

4. A gas diffusion layer with a slot structure according to claim 1, characterized in that, The depth of the slots is the same as the thickness of the gas diffusion layer; the length of the slots is equal to the distance between the edges of two adjacent flow channels in the flow channel plate; the porous substrate of the gas diffusion layer is formed between any adjacent slots, forming a ridge-like structure, and the ridge width is equal to the slot pitch.

5. A gas diffusion layer with a slot structure according to claim 1, characterized in that, The central axis of each slot passes through the middle position between two slots in the adjacent row.

6. A gas diffusion layer with a slot structure according to any one of claims 1-5, characterized in that, The gas diffusion layer is first combined with a ccm membrane and a sealing frame made of a PET membrane to form a membrane electrode. The membrane electrode achieves a positioning relationship with the flow field plate through the sealing frame to complete the positioning between the slots and the flow channels.

7. An optimization method for the slot structure in the gas diffusion layer according to any one of claims 1-6, characterized in that, It includes the following steps: Locate and determine the initial layout of the slots in the gas diffusion layer according to the flow channel layout of the flow field plate; Adjust the structural parameters of the slots, and then perform numerical simulation on the battery to obtain the output performance curve of the battery. Among them, the structural parameters include the slot pitch, quantity, width, and inclination angle; Compare the output performance of the battery before and after adjustment, and screen out the structural parameters corresponding to the highest performance.

8. The optimization method according to claim 7, wherein The flow channel layout of the flow field plate is any one of a parallel flow field layout, a serpentine flow field layout, and an interdigitated flow field layout. Adjust the structural parameters of the slots to obtain a porous auxiliary channel for drainage and mass transfer that fits the flow channel layout.

9. The optimization method according to claim 8, wherein Make the slots in the gas diffusion layer close to the corners of the flow channels.

10. A preparation method of a gas diffusion layer with a slot structure, characterized in that, After determining the structural parameters of the slots in the gas diffusion layer by the optimization method according to any one of claims 7-9, prepare the gas diffusion layer. The preparation method includes the following steps: Use the pre-drawn filling pattern and laser parameters in a laser device to perform laser processing on the gas diffusion layer; After processing the slots, perform hydrophobic treatment on the gas diffusion layer, take it out and dry it, and then perform heat treatment.

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