Fuel cell gas diffusion layer containing wave channels, preparation method and application

Abstract

The invention discloses a fuel cell gas diffusion layer containing a wave channel, and a preparation method and application thereof. The preparation method comprises the following steps: cutting a substrate layer material and designing the wave channel; the substrate layer material is placed on a laser etching adsorption platform, laser etching is conducted on the first surface of the substrate layer material, a wave channel is obtained, and the extending direction of the wave channel is parallel to the length direction of the substrate layer material; carrying out hydrophobic treatment on the substrate layer material containing the wave channel; then mixing and stirring conductive carbon black, a binder, an emulsion and water to obtain microporous layer slurry; and finally, spraying the microporous layer slurry on the second surface of the substrate layer material, and then drying, thermally treating and curing the substrate layer material to obtain the fuel cell gas diffusion layer containing the wave channels. According to the fuel cell gas diffusion layer containing the wave channels, the mass transfer rate can be increased, transmission and supply of hydrogen and oxygen in air are improved, generated water is effectively discharged, and aggregation of liquid water in the flow channels is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a novel integrated fuel cell gas diffusion layer with a functional wave channel, a preparation method and an application thereof. Background Art

[0002] A fuel cell is a device that converts chemical energy directly into electrical energy through an electrochemical reaction. Its core components include a proton exchange membrane, a catalyst, and a gas diffusion layer. As a key component connecting the electrode and the bipolar plate, the gas diffusion layer not only supports the catalyst layer and stabilizes the electrode structure, but also performs the important functions of conducting gas, electrons, heat, and discharging the reaction product water. The traditional gas diffusion layer is usually composed of a base layer (GDB) and a microporous layer (MPL). The base layer is mostly made of carbon paper or carbon cloth, while the microporous layer is made by coating a slurry containing carbon powder, a hydrophobic agent, and other additives. Although this structure meets the basic needs of fuel cells to a certain extent, it still has shortcomings in terms of high power density output and efficient water management. Especially inside the fuel cell, water management has a direct impact on power output, and the existing gas diffusion layer still has room for improvement in drainage performance and mass transfer efficiency.

[0003] Chinese patent CN113178591B discloses a gas diffusion layer for a proton exchange membrane fuel cell and its processing technology; the surface of the gas diffusion layer close to the bipolar plate is distributed as a gradient wavy micro-groove structure, the groove structure is located between the inlet section and the outlet section of the gas diffusion layer, the groove structure is a gradient structure with an amplitude increasing synchronously along the gas flow direction and wavelength, and the drainage capacity of different water contents and strengths is achieved by setting the gradient distribution grooves to ensure the consistency of the gas flow direction and water distribution; however, the base surface of the gas diffusion layer has a gradient hole or a concave-convex structure, and only in this device of the gas diffusion layer, there is no integrated bipolar plate functional characteristics in it, and the gas diffusion layer has problems of gas transport and drainage difficulties under high current density, which is not conducive to the removal of nitrogen in hydrogen and nitrogen, affecting battery attenuation; the single cell voltage is low. Summary of the invention

[0004] The gas diffusion layer of the fuel cell in the prior art has the defects of single performance, resistance to gas transport and drainage at high electric density, and is not conducive to the discharge of nitrogen in hydrogen and nitrogen, which affects the battery life. To provide a fuel cell gas diffusion layer containing a wave channel with diversified performance, which can solve the gas transport and drainage resistance at high electric density, alleviate the flooding problem and effectively discharge nitrogen in the hydrogen and nitrogen mixture, and has little impact on the battery, as well as a preparation method and application.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a method for preparing a fuel cell gas diffusion layer containing a wavy channel, comprising the following steps: step one: cutting a base layer material and designing a structure of a wavy channel; step two: placing the cut base layer material on a laser etching adsorption platform, laser etching the first surface of the base layer material in combination with the designed wavy channel structure, and obtaining a wavy channel on the first surface, wherein the extension direction of the wavy channel is parallel to the length direction of the base layer material; step three: performing a hydrophobic treatment on the base layer material containing the wavy channel; step four: mixing and stirring conductive carbon black, a binder, an emulsion and water to obtain a microporous layer slurry with a viscosity of 1000 to 2000 Pa·s; step five: spraying the microporous layer slurry on the second surface of the base layer material relative to the first surface, and drying the base layer material after spraying; after drying, the base layer material is heat-treated and cured to obtain a fuel cell gas diffusion layer containing a wavy channel.

[0006] Furthermore, in step 1, the base layer material is prepared from a carbon material, and the thickness of the base layer material is in the range of 100 to 200 um.

[0007] Further, in step 1, the structure of the wave channel is a cosine function structure or a sine function structure. When the structure of the wave channel is a sine function structure, the structure of the wave channel is:

[0008] Y=a+1 / 4sin(1 / 2*πx+b)

[0009] Where a and b are both constants;

[0010] When the structure of the wave channel is a cosine function structure, the structure of the wave channel is:

[0011] Y=a+1 / 4cos(1 / 2*πx+b-π / 2)

[0012] Where a and b are both constants.

[0013] Furthermore, in step three, in an ultrasonic environment, polytetrafluoroethylene is loaded on the surface of the base layer material so that the polytetrafluoroethylene penetrates into the base layer material and forms a hydrophobic layer, and the loading amount of the polytetrafluoroethylene is 10 to 30 wt%.

[0014] Furthermore, in step 4, the mass fraction of the conductive carbon black in the microporous layer slurry is in the range of 5-20%, the binder is polyvinyl pyrrolidone, the mass fraction of the binder is 5%, and the emulsion is polytetrafluoroethylene, the mass fraction of the emulsion is in the range of 2-10%.

[0015] Furthermore, in step five, the microporous layer slurry is sprayed on the second surface of the base layer material relative to the first surface. After spraying, the base layer material is dried at a temperature of 100°C for 10 to 30 minutes; after drying, the base layer material is placed in an environment of 200 to 400°C for heat treatment and curing, and the curing time is 20 to 40 minutes.

[0016] The present application also discloses a fuel cell gas diffusion layer containing wavy channels, including a substrate layer, a first surface of the substrate layer having a plurality of wavy channels fixed thereon, the extension direction of the wavy channels being parallel to the length direction of the substrate layer, and there being spacings between the plurality of wavy channels; the shape of the wavy channels being a sine function structure or a cosine function structure; a second surface of the substrate layer opposite to the first surface is provided with a microporous layer slurry made of polytetrafluoroethylene, and the viscosity of the microporous layer slurry is in the range of 1000 to 2000 Pa.s.

[0017] Furthermore, the period of the wave channel is 1 to 3, the distance between two adjacent troughs of the wave channel is in the range of 0.5 to 1.5 mm, the distance between two adjacent peaks of the wave channel is in the range of 0.5 to 1.5 mm, and the height of the peaks of the wave channel is in the range of 0.5 to 1.5 mm.

[0018] Furthermore, the contact angle of the base layer ranges from 100 to 121°, and the resistivity of the base layer ranges from 4.0 to 6.37 mΩ·cm.

[0019] The present application also discloses a fuel cell, comprising a fuel cell gas diffusion layer containing a wave channel.

[0020] The present invention discloses a fuel cell gas diffusion layer containing a wave channel, a preparation method and an application thereof. The flow channel structure of the function is laser processed on the top surface of the carbon paper substrate bottom layer, and a microporous layer is coated on the bottom surface of the carbon paper substrate bottom layer after hydrophobic treatment, which is conducive to timely removing nitrogen in the hydrogen and nitrogen during the introduction of hydrogen and nitrogen, avoiding the generation of nitrogen accumulation, thereby improving the power generation efficiency of the fuel cell using hydrogen and nitrogen as fuel; at the same time, the wave channel structure using a sine function and a cosine function type structure can match the flow direction of the gas and the function of the bipolar plate, so the bipolar plate device can be omitted, thereby improving the overall integration degree; the wave-shaped surface structure and porous ribs make the flow state in the channel present a turbulent state, thereby accelerating the mass transfer rate, especially at high current density, improving the transmission and supply of hydrogen in hydrogen and nitrogen and oxygen in the air; more effectively distributing the reaction gas, reducing the dead zone of gas flow, thereby improving the reaction efficiency; in addition, the gas diffusion of the integrated flow channel structure has abundant microtunnels, excellent gas transfer and water management capabilities, and can more effectively discharge the generated water, reduce the accumulation of liquid water in the flow channel, and reduce the risk of flooding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic structural diagram of a fuel cell gas diffusion layer containing a wave channel according to the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The method for preparing a fuel cell gas diffusion layer containing a wave channel according to the present invention comprises the following steps:

[0025] Step 1: Cut the base material and design the structure of the wave channel;

[0026] Step 2: placing the cut base layer material on a laser etching adsorption platform, and laser etching the first surface of the base layer material in combination with the designed wave channel structure to obtain a wave channel on the first surface, wherein the extension direction of the wave channel is parallel to the length direction of the base layer material;

[0027] Step 3: Performing hydrophobic treatment on the base layer material containing the wave channel;

[0028] Step 4: Mix and stir the conductive carbon black, the binder, the emulsion and water to obtain a microporous layer slurry with a viscosity of 1000 to 2000 Pa·s;

[0029] Step five: spray the microporous layer slurry on the second surface of the base layer material opposite to the first surface, and dry the base layer material after spraying; after drying, heat treat and solidify the base layer material to obtain a fuel cell gas diffusion layer containing a wave channel.

[0030] In step one, a carbon material base layer material, such as carbon paper, is used as the base layer material; preferably, the base layer material is a carbon material base layer material that has not been hydrophobically treated, and the thickness of the base layer material is 100 to 200 um; the base layer material is cut into a specific size, such as 50*50 mm, in combination with the application in the fuel cell; for the subsequent preparation of the fuel cell gas diffusion layer.

[0031] Among them, the structure of the wave channel is a functional structure, the structure of the wave channel is a cosine function structure or a sine function structure, and the structure of the wave channel is designed and calculated by three-dimensional design software; when the structure of the wave channel is a sine function, the structure of the wave channel satisfies the following sine function equation:

[0032] Y=a+1 / 4sin(1 / 2*πx+b)

[0033] Where a and b are constants, such as 0;

[0034] When the wave channel structure is a cosine function, the wave channel structure satisfies the following cosine function equation:

[0035] Y=a+1 / 4cos(1 / 2*πx+b-π / 2)

[0036] Where a and b are constants, such as 0;

[0037] In order to increase the pressure in the subsequent fluid flow process, balance the reaction rate of the fuel cell during operation, and improve the reaction uniformity of the gas in the gas diffusion layer; specifically, the period of the wave channel function is 1 to 3, the distance between two adjacent troughs of the wave channel function is in the range of 0.5 to 1.5 mm, the distance between two adjacent peaks of the wave channel function is in the range of 0.5 to 1.5 mm, and the height of the peak of the wave channel function is in the range of 0.5 to 1.5 mm; by adopting a functional wave channel structure, the pressure of each part inside the channel during the fluid flow process is uniform, the gas undergoes oxidation reaction or reduction reaction during the flow process, and the gas reaction rate is relatively uniform under the action of the wave channel. In addition, due to the constantly changing bending structure of the wave channel, the flow direction of the gas changes continuously during the flow process. The constantly changing flow direction can enhance the mass transfer of the peaks of the wave channel and improve the diffusion effect of the gas, thereby improving the electrochemical reaction rate of the gas and the gas utilization rate.

[0038] In step 2, the base layer material made of carbon material that has been cut in step 1 is placed on a laser etching adsorption platform, and the operating parameters of the laser marking machine, including power, focal length, current, etching times and beam wavelength, are adjusted. In combination with the wave channel with a functional structure designed in step 1, the upper surface of the base layer material made of carbon material that has been cut is laser etched to form a wave channel with a functional structure designed in step 1 on the upper surface of the base layer material; by setting a wave structure with a functional shape on the base layer material made of carbon material by laser etching, the flow of gas in the channel is turbulent, and the mass transfer efficiency is accelerated, especially at high current density, the transmission and supply of hydrogen in hydrogen and nitrogen and oxygen in the air are improved, and the wave channel using the functional structure can act as a gas flow field, so that the bipolar plate device in the traditional fuel cell can be omitted, thereby improving the degree of integration of the fuel cell.

[0039] In step three, a polytetrafluoroethylene (PTFE) emulsion is used to perform hydrophobic treatment on the substrate material containing the wave channel after laser etching, so as to improve the waterproof effect of the gas diffusion layer, optimize the structure of the gas diffusion layer, maintain stable hydrophobic performance under high temperature or high pressure environment, and ensure the long-term stable operation of the fuel cell. Specifically, polytetrafluoroethylene (PTFE) is loaded on the surface of the substrate material after laser etching; preferably, the polytetrafluoroethylene (PTFE) emulsion is used for immersion treatment under ultrasonic environment, so that the PTFE emulsion penetrates into the substrate more evenly. A uniform hydrophobic layer is formed in the internal structure of the material, which improves the permeability and conductivity of the gas diffusion layer, thereby improving the overall performance of the fuel cell; wherein, in the process of increasing the emulsion, the contact angle will increase due to the loading amount of the emulsion, and at the same time, the resistivity of the gas diffusion layer will increase. In order to ensure sufficient conductivity during operation, it is more preferred that the loading amount of polytetrafluoroethylene (PTFE) ranges from 10 to 30wt%, the contact angle range of the substrate material supported by the carbon material is 100 to 121°, and the resistivity of the substrate material after loading is controlled at 4 to 6.37mΩ·cm.

[0040] In step 4, conductive carbon black, a binder, an emulsion and water are mixed to obtain a microporous layer slurry with a viscosity of 1000 to 2000 Pa·s. Specifically, conductive carbon black with a mass fraction of 5 to 20%, 5% polyvinyl pyrrolidone (PVP) binder, 2 to 10% polytetrafluoroethylene (PTFE) emulsion, and 50 to 80% water are selected and mixed and stirred at room temperature to form a microporous layer slurry with a viscosity range of 1000 to 2000 Pa.S. By preparing a microporous layer slurry with a viscosity range of 1000 to 2000 Pa.S, when the slurry is subsequently coated on a base layer material, the slurry has a higher conductivity under the action of the conductive carbon black, and the slurry with a microporous structure also has a certain hydrophobicity, which is beneficial for the water generated during the gas reaction to be discharged from the catalyst layer through the microporous structure and enter the gas diffusion layer.

[0041] In step five, the microporous layer slurry prepared in step four is sprayed on the second surface of the base layer material opposite to the first surface by spraying, roller coating or screen printing. After the spraying of the microporous layer slurry on the second surface of the base layer material is completed, the base layer material after spraying is placed in an oven at 100°C for 10 to 30 minutes to achieve preliminary strengthening and fixation of the microporous layer slurry; by spraying the microporous layer slurry on the second surface of the base layer material, and the microporous layer slurry is arranged opposite to the functional wave channel, a rich The micro-tunnel structure is beneficial to the gas transfer and water discharge during the reaction process, can effectively discharge the generated water, reduce the accumulation of liquid water in the flow channel, reduce the risk of flooding, and is beneficial to promoting the electrochemical reaction and the generation of electrons, ensuring the efficient use of the catalyst, and improving the water management of the fuel cell; after drying, the dried base layer material containing the functional wave channel and the microporous layer slurry is further heat-treated and cured in an environment of 200 to 400°C for 20 to 40 minutes; and a fuel cell gas diffusion layer containing a wave channel is obtained.

[0042] The preparation method of the fuel cell gas diffusion layer containing the wave channel is further described below in conjunction with the embodiment:

[0043] Step 1: Select carbon paper as the base material, cut the base material into a rectangular structure, the thickness of the base material is 100um, and the structure of the wave channel is designed to be a sine function. The structure of the wave channel satisfies the following function equation;

[0044] Y=1 / 4sin(1 / 2*πx)

[0045] Step 2: placing the cut carbon paper base layer material on a laser etching adsorption platform, laser etching the first surface of the base layer material in combination with the wave channel structure of the sine function structure, and obtaining a wave channel containing the sine function structure on the first surface;

[0046] Step 3: Using polytetrafluoroethylene (PTFE) to perform hydrophobic treatment on the substrate material containing the wave channel under an ultrasonic environment, wherein the loading amount of polytetrafluoroethylene is 10wt%, the contact angle of the carbon paper substrate material is 100°, and the resistivity after loading polytetrafluoroethylene is 4mΩ·cm;

[0047] Step 4: Select a conductive carbon black with a mass fraction of 5%, a polyvinyl pyrrolidone (PVP) binder of 5%, a polytetrafluoroethylene (PTFE) emulsion of 2%, and a water tank of 50%, and mix them and stir at room temperature to form a microporous layer slurry with a viscosity range of 1000 Pa.S;

[0048] Step 5: Spray the microporous layer slurry on the second surface of the base layer material. After spraying, dry the base layer material in an oven at 100°C for 10 minutes. After drying, heat treat and cure the base layer material in an environment of 200°C for 20 minutes to obtain a fuel cell gas diffusion layer containing a wavy channel.

[0049] Example 2

[0050] Step 1: Select carbon paper as the base material, cut the base material into a rectangular structure, the thickness of the base material is 150um, and the structure of the wave channel is designed to be a sine function. The structure of the wave channel satisfies the following function equation;

[0051] Y=1 / 4sin(1 / 2*πx)

[0052] Step 2: placing the cut carbon paper base layer material on a laser etching adsorption platform, laser etching the first surface of the base layer material in combination with the wave channel structure of the sine function structure, and obtaining a wave channel containing the sine function structure on the first surface;

[0053] Step 3: Using polytetrafluoroethylene (PTFE) to perform hydrophobic treatment on the substrate material containing the wave channel under an ultrasonic environment, wherein the loading amount of polytetrafluoroethylene is 20wt%, the contact angle of the carbon paper substrate material is 110°, and the resistivity after loading polytetrafluoroethylene is 5mΩ·cm;

[0054] Step 4: Select conductive carbon black with a mass fraction of 10%, polyvinyl pyrrolidone (PVP) binder 5%, polytetrafluoroethylene (PTFE) emulsion 6%, and 70% water tank, mix and stir at room temperature to form a microporous layer slurry with a viscosity range of 1500 Pa.S;

[0055] Step 5: Spray the microporous layer slurry on the second surface of the base layer material. After spraying, dry the base layer material in an oven at 100°C for 20 minutes. After drying, heat treat and cure the base layer material in an environment of 300°C for 30 minutes to obtain a fuel cell gas diffusion layer containing a wavy channel.

[0056] Example 3

[0057] Step 1: Select carbon paper as the base material, cut the base material into a rectangular structure, the thickness of the base material is 200um, and the structure of the wave channel is designed to be a sine function. The structure of the wave channel satisfies the following function equation;

[0058] Y=1 / 4cos(1 / 2*πx-π / 2)

[0059] Step 2: placing the cut carbon paper base layer material on a laser etching adsorption platform, laser etching the first surface of the base layer material in combination with the wave channel structure of the sine function structure, and obtaining a wave channel containing the sine function structure on the first surface;

[0060] Step 3: Using polytetrafluoroethylene (PTFE) to perform hydrophobic treatment on the substrate material containing the wave channel under an ultrasonic environment, wherein the loading amount of polytetrafluoroethylene is 30wt%, the contact angle of the carbon paper substrate material is 121°, and the resistivity after loading polytetrafluoroethylene is 6.37mΩ·cm;

[0061] Step 4: Select conductive carbon black with a mass fraction of 20%, 5% polyvinyl pyrrolidone (PVP) binder, 10% polytetrafluoroethylene (PTFE) emulsion, and 80% water tank, mix and stir at room temperature to form a microporous layer slurry with a viscosity range of 2000 Pa.S;

[0062] Step 5: Spray the microporous layer slurry onto the second surface of the base layer material. After spraying, dry the base layer material in an oven at 100°C for 30 minutes. After drying, heat treat and cure the base layer material in an environment of 400°C for 40 minutes to obtain a fuel cell gas diffusion layer containing a wavy channel.

[0063] like Figure 1 As shown, the present application also discloses a fuel cell gas diffusion layer containing wavy channels prepared by the above-mentioned method for preparing a fuel cell gas diffusion layer containing wavy channels, comprising a substrate layer 1:

[0064] A plurality of wave channels 2 are fixed on the first surface of the base layer 1, the extension direction of the wave channels 2 is parallel to the length direction of the base layer, and there are intervals between the plurality of wave channels 2; the shape of the wave channels 2 is a sine function structure or a cosine function structure;

[0065] A microporous layer slurry 3 made of polytetrafluoroethylene is disposed on a second surface of the base layer 1 opposite to the first surface. The viscosity of the microporous layer slurry 3 is in the range of 1000 to 2000 Pa.s.

[0066] Wherein, the manufacturing material of the base layer 1 is a carbon material, such as carbon paper, the cross-sectional shape of the base layer 1 is a rectangular structure, and the thickness of the base layer 1 ranges from 100 to 200 um; when the shape of the wave channel 2 is a sine function structure, the shape of the following sine function equation of the structure of the wave channel 2 is the same;

[0067] Y=1 / 4sin(1 / 2*πx)

[0068] When the shape of the wave channel 2 is a cosine function structure, the structure of the wave channel 2 is the same as the shape of the following cosine function equation;

[0069] Y=1 / 4cos(1 / 2*πx-π / 2)

[0070] Further; the period of the wave channel 2 is 1 to 3, the distance between two adjacent troughs of the wave channel 2 is in the range of 0.5 to 1.5 mm, the distance between two adjacent crests of the wave channel 2 is in the range of 0.5 to 1.5 mm, and the height of the crest of the wave channel 2 is in the range of 0.5 to 1.5 mm; preferably, the period of the wave channel 2 is 1, the distance between two adjacent troughs of the wave channel 2 is 0.5 mm, the distance between two adjacent crests of the wave channel 2 is 0.5 mm, and the crest height of the wave channel 2 is 0.5 mm;

[0071] In order to improve the diffusion performance of gas in the gas diffusion layer, while improving the conductivity and drainage capacity of the gas diffusion layer, and reducing the influence of water on the electrochemical reaction, preferably, the substrate 1 is also loaded with polytetrafluoroethylene, and the loading amount of polytetrafluoroethylene on the substrate is 10-30wt%, the contact angle range of the substrate 1 made of carbon material is 100-121°, and the resistivity of the substrate 1 after loading is controlled at 4.0-6.37mΩ·cm; the microporous layer slurry 3 on the second surface of the substrate 1 is prepared by mixing and stirring 5-20% conductive carbon black, 5% PVP (polyvinyl pyrrolidone) binder, 2-10% PTFE emulsion and 50-80% water; thereby having higher conductivity and hydrophobicity, facilitating the discharge of water generated by the catalytic layer from the gas diffusion layer, and reducing the aggregation of liquid water and the risks arising therefrom.

[0072] The present application also discloses a fuel cell, comprising a fuel cell gas diffusion layer containing wavy channels prepared by the above-mentioned method for preparing a fuel cell gas diffusion layer containing wavy channels.

[0073] The present application discloses a fuel cell gas diffusion layer containing a wavy channel, a preparation method and an application thereof. The flow channel structure of the laser processing function is performed on the top surface of the carbon paper substrate bottom layer, and a microporous layer is coated on the bottom surface of the carbon paper substrate bottom layer after hydrophobic treatment, which is conducive to timely removing nitrogen in the hydrogen and nitrogen during the introduction of hydrogen and nitrogen, avoiding the generation of nitrogen accumulation, thereby improving the power generation efficiency of the fuel cell using hydrogen and nitrogen as fuel; at the same time, the wavy channel structure using sine function and cosine function type structure can match the flow direction of the gas and the function of the bipolar plate, so the bipolar plate device can be omitted, thereby improving the overall integration degree; the wavy surface structure and porous ribs make the flow state in the channel present a turbulent state, thereby accelerating the mass transfer rate, especially at high current density, improving the transmission and supply of hydrogen in hydrogen and nitrogen and oxygen in the air; more effectively distribute the reaction gas, reduce the dead zone of gas flow, thereby improving the reaction efficiency; in addition, the gas diffusion of the integrated flow channel structure has abundant microtunnels, excellent gas transfer and water management capabilities, can more effectively discharge the generated water, reduce the accumulation of liquid water in the flow channel, and reduce the risk of flooding.

[0074] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. However, the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for preparing a fuel cell gas diffusion layer containing a wave channel, characterized in that: The steps include: Step 1: Cut the base material and design the structure of the wave channel; Step 2: placing the cut base layer material on a laser etching adsorption platform, and laser etching the first surface of the base layer material in combination with the designed wave channel structure to obtain a wave channel on the first surface, wherein the extension direction of the wave channel is parallel to the length direction of the base layer material; Step 3: Performing hydrophobic treatment on the base material containing the wave channel; Step 4: Mix and stir the conductive carbon black, the binder, the emulsion and water to obtain a microporous layer slurry with a viscosity of 1000 to 2000 Pa·s; Step five: spray the microporous layer slurry on the second surface of the base layer material opposite to the first surface, and dry the base layer material after spraying; after drying, heat treat and solidify the base layer material to obtain a fuel cell gas diffusion layer containing a wave channel.

2. The method for preparing a fuel cell gas diffusion layer containing a wave channel according to claim 1, characterized in that: In step 1, the base layer material is made of carbon material, and the thickness of the base layer material is in the range of 100 to 200 um.

3. The method for preparing a fuel cell gas diffusion layer containing a wave channel according to claim 1, characterized in that: In step 1, the structure of the wave channel is a cosine function structure or a sine function structure. When the structure of the wave channel is a sine function structure, the structure of the wave channel is: Y=a+1 / 4sin(1 / 2*πx+b) Where a and b are both constants; When the structure of the wave channel is a cosine function structure, the structure of the wave channel is: Y=a+1 / 4cos(1 / 2*πx+b-π / 2) Where a and b are both constants.

4. The method for preparing a fuel cell gas diffusion layer containing a wave channel according to claim 1, characterized in that: In step three, in an ultrasonic environment, polytetrafluoroethylene is loaded on the surface of the base layer material, so that the polytetrafluoroethylene penetrates into the base layer material and forms a hydrophobic layer, and the loading amount of the polytetrafluoroethylene is 10 to 30 wt%.

5. The method for preparing a fuel cell gas diffusion layer containing a wave channel according to claim 1, characterized in that: In step 4, the mass fraction of the conductive carbon black in the microporous layer slurry is in the range of 5-20%, the binder is polyvinyl pyrrolidone, the mass fraction of the binder is 5%, and the emulsion is polytetrafluoroethylene, the mass fraction of the emulsion is in the range of 2-10%.

6. The method for preparing a fuel cell gas diffusion layer containing a wave channel according to claim 1, characterized in that: In step five, the microporous layer slurry is sprayed on the second surface of the base layer material relative to the first surface. After spraying, the base layer material is dried at a temperature of 100°C for 10 to 30 minutes. After drying, the base layer material is placed in an environment of 200 to 400°C for heat treatment and curing, and the curing time is 20 to 40 minutes.

7. A fuel cell gas diffusion layer containing wavy channels prepared by the method for preparing a fuel cell gas diffusion layer containing wavy channels according to any one of claims 1 to 6, comprising a substrate layer, characterized in that: A plurality of wave channels are fixed on the first surface of the base layer, the extension direction of the wave channels is parallel to the length direction of the base layer, and there are intervals between the plurality of wave channels; The shape of the wave channel is a sine function structure or a cosine function structure; A microporous layer slurry made of polytetrafluoroethylene is arranged on a second surface of the base layer opposite to the first surface, and the viscosity of the microporous layer slurry is in the range of 1000 to 2000 Pa.s.

8. A fuel cell gas diffusion layer containing a wave channel according to claim 7, characterized in that; The period of the wave channel is 1 to 3, the distance between two adjacent troughs of the wave channel is in the range of 0.5 to 1.5 mm, the distance between two adjacent crests of the wave channel is in the range of 0.5 to 1.5 mm, and the height of the crests of the wave channel is in the range of 0.5 to 1.5 mm.

9. A fuel cell gas diffusion layer containing a wave channel according to claim 7, characterized in that; The contact angle of the base layer is in the range of 100 to 121 degrees, and the resistivity of the base layer is in the range of 4.0 to 6.37 mΩ·cm.

10. A fuel cell, characterized in that: A fuel cell gas diffusion layer comprising a wave channel as described in any one of claims 7 to 9.

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