CN115000443A - Membrane electrode for fuel cell, gas diffusion layer and preparation method thereof - Google Patents

Membrane electrode for fuel cell, gas diffusion layer and preparation method thereof Download PDF

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Publication number
CN115000443A
CN115000443A CN202210671469.2A CN202210671469A CN115000443A CN 115000443 A CN115000443 A CN 115000443A CN 202210671469 A CN202210671469 A CN 202210671469A CN 115000443 A CN115000443 A CN 115000443A
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China
Prior art keywords
layer
gas diffusion
diffusion layer
microporous
plane
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万贺廷
方川
李文文
袁殿
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Beijing Sinohytec Co Ltd
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Beijing Sinohytec Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/023—Porous and characterised by the material
    • H01M8/0241—Composites
    • H01M8/0245—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Abstract

The invention provides a preparation method of a gas diffusion layer for a fuel cell, belongs to the technical field of fuel cells, and solves the problem that the gas diffusion layer and a five-in-one membrane electrode are easy to separate when a full-size membrane electrode prepared in the prior art is used. The method comprises preparing a microporous layer of uniform thickness on a substrate layer to obtain an initial gas diffusion layer; after the initial gas diffusion layer is placed on a smooth horizontal plane and fixed, applying a pressure of 0.1-1.0 MPa vertically upwards or downwards to press and bond the microporous layer and the substrate layer until the stress concentration phenomenon is eliminated; and uniformly coating the glue on the top edge of the microporous layer to finish the preparation of the gas diffusion layer for the fuel cell. And respectively bonding and fixing the cathode gas diffusion layer and the anode gas diffusion layer with the first frame membrane of the five-in-one membrane electrode to obtain the membrane electrode for the fuel cell, which has more stable structure and better gas diffusion performance than the prior art.

Description

Membrane electrode for fuel cell, gas diffusion layer and preparation method thereof
Technical Field
The invention relates to the technical field of fuel cells, in particular to a membrane electrode for a fuel cell, a gas diffusion layer and a preparation method of the membrane electrode.
Background
The fuel cell stack is composed of an end plate, an insulating plate, a current collecting plate, a bipolar plate and a full-size membrane electrode, and is assembled through pressing force. The full-size membrane electrode is used as the core of the fuel cell stack and comprises a catalyst layer, a proton exchange membrane, a frame membrane and a gas diffusion layer. During preparation, the cathode catalyst layer and the anode catalyst layer are respectively transferred to a proton exchange membrane through coating to obtain a three-in-one membrane electrode, the three-in-one membrane electrode is fixed through a frame membrane to form a five-in-one membrane electrode, and finally the five-in-one membrane electrode and a gas diffusion layer are pressed to complete the preparation of the full-size membrane electrode.
When electrochemical reaction occurs, hydrogen molecules on the anode side lose electrons to become protons under the action of the catalyst in the full-size membrane electrode, and reach the cathode side through the proton exchange membrane to obtain electrons under the action of the cathode catalyst and combine with oxygen molecules to generate water. In this process, the proton exchange membrane needs to maintain a certain moisture content to maintain a high proton conductivity. The proton exchange membrane needs the support of the gas diffusion layer in the process of maintaining the performance.
When the existing full-size membrane electrode is prepared, glue is usually used for attaching the gas diffusion layer to the five-in-one membrane electrode. However, because the gas diffusion layer and the pentahapto membrane electrode are not firmly bonded, the gas diffusion layer and the pentahapto membrane electrode are separated and even fall off in the processes of air tightness detection, packaging and warehousing and the like along with the change of external conditions, such as the change of indoor temperature and humidity and the non-standard operation of people.
Disclosure of Invention
In view of the foregoing analysis, embodiments of the present invention provide a membrane electrode for a fuel cell, a gas diffusion layer, and a method for manufacturing the same, so as to solve the problem that the gas diffusion layer and the five-in-one membrane electrode are easily separated when a full-scale membrane electrode manufactured in the prior art is used.
In one aspect, an embodiment of the present invention provides a method for preparing a gas diffusion layer for a fuel cell, including the following steps:
preparing a microporous layer (2) with uniform thickness on a substrate layer (1) to obtain an initial gas diffusion layer;
after the initial gas diffusion layer is placed on a smooth horizontal plane and fixed, applying pressure of 0.1-1.0 MPa vertically upwards or downwards to press and bond the microporous layer (2) and the substrate layer (1) until the stress concentration phenomenon is eliminated, and forming a pressed substrate layer (4) and a pressed microporous layer (5);
and (3) uniformly coating the glue on the top edge of the laminated microporous layer (5) to finish the preparation of the gas diffusion layer for the fuel cell.
The beneficial effects of the above technical scheme are as follows: the preparation method for pre-pressing the gas diffusion layer to eliminate the stress concentration phenomenon is provided, and the packaging qualification rate of the gas diffusion layer in the full-size membrane electrode can be effectively improved. Under a smaller pressure, the microporous layer (2) with a loose structure in the initial gas diffusion layer is pressed and the substrate layer (1) is compressed, so that the integrity and the cohesiveness of the substrate layer (4) and the microporous layer (5) after being pressed are improved, and then the glue is coated on the top edge of the microporous layer (5) after being pressed, so that when the gas diffusion layer is bonded with the five-in-one membrane electrode, the packaging strength between the gas diffusion layer and the five-in-one membrane electrode is enhanced, the stress concentration phenomenon is improved, and the gas diffusion performance is unchanged.
Based on the further improvement of the method, the material of the substrate layer (1) comprises at least one of carbon paper, carbon cloth, porous ceramic plate, bamboo fiber woven plate, carbon felt, metal net, metal felt, metal foam and porous fiber membrane; and the number of the first and second electrodes,
the material of the microporous layer (2) comprises at least one of an elastic carbon nanotube porous layer, an elastic graphene porous layer, an elastic carbon fiber porous layer, an elastic carbon felt or elastic carbon paper.
Further, the step of preparing a microporous layer (2) of uniform thickness on the substrate layer (1) to obtain an initial gas diffusion layer further comprises:
preparing a substrate layer (1) with porous gas transmission channels;
uniformly coating the microporous layer slurry on the upper surface of the substrate layer (1);
connecting a vacuum pump with the substrate layer coated with the microporous layer slurry, vacuumizing, performing adsorption pre-infiltration treatment, and then sequentially drying and sintering; wherein the drying temperature is 60-80 ℃, the drying time is 6-24 h, the sintering temperature is 250-400 ℃, and the sintering time is 60-110 min;
and pre-pressing the sintered substrate layer coated with the microporous layer slurry to obtain the initial gas diffusion layer.
Further, the thickness of the substrate layer (1) is 90-200 μm; and the number of the first and second electrodes,
the coating thickness of the microporous layer slurry is 30-80 μm.
Further, the step of applying a pressure of 0.1 to 1.0 MPa vertically upward or downward to press and bond the microporous layer (2) and the substrate layer (1) after the initial gas diffusion layer is fixed on a smooth horizontal plane until the stress concentration phenomenon is eliminated is identified further comprises:
uniformly distributing a plurality of stress sensors at the bottom of a substrate layer (1) of the initial gas diffusion layer;
placing the initial gas diffusion layer provided with the stress sensor on a smooth horizontal plane for fixing, so that the microporous layer (2) faces upwards;
applying downward pressure of 0.1-1.0 MPa to the initial gas diffusion layer for 6-20 s through the mould pressing plate (3)FSo as to press and bond the microporous layer (2) and the substrate layer (1);
and in the laminating process, monitoring stress data acquired by each stress sensor until all the stress data exceed a set value and the variance of all the stress data is lower than a preset variance upper limit, judging that the stress concentration phenomenon is eliminated, stopping laminating, and removing the stress sensors to obtain the laminated microporous layer (5) and the laminated substrate layer (4).
Further, the bottom of the mould pressing plate (3) is a smooth horizontal plane or a plane with multiple layers of steps; wherein the content of the first and second substances,
for low-viscosity glue, adopting a mould pressing plate (3) with a smooth horizontal plane at the bottom to obtain a laminated microporous layer (5) with a smooth horizontal plane at the surface deviating from the laminated substrate layer (4); and the number of the first and second electrodes,
for the high-viscosity glue, a mould pressing plate (3) with a plurality of layers of stepped planes at the bottom is adopted, the number of steps is more than or equal to 2, and a laminated microporous layer (5) with a plurality of stepped planes on one surface departing from the laminated base layer (4) is obtained.
Further, the pressure isFObtained by the following formula
F=f（T，S，Q max ，Q mi n，F Packaging force ）
In the formula (I), the compound is shown in the specification,Tis the preset temperature of the stack air when the fuel cell works,Sthe preset humidity of the air entering the stack when the fuel cell works,Q max the preset maximum ventilation quantity of the stack air when the fuel cell works,Q min a preset minimum ventilation of stack air during fuel cell operation,F packaging force To maintain a minimum packing force of the gas diffusion layer under membrane electrode performance,f() Is a fitting function.
Further, a pressing plate (3) with three layers of step-shaped planes at the bottom applies pressure with the downward value of 0.5-0.9 MPa and the pressing time of 10-15 s to the initial gas diffusion layerFLaminating and bonding the microporous layer (2) and the substrate layer (1), and forming three stepped planes on the top of the laminated microporous layer (5), wherein the three planes formed from top to bottom are a first microporous plane (6), a second microporous plane (7) and a third microporous plane (8) in sequence; the area of the first micropore plane (6) exceeds 4/5 of the total plane area of the three-layer step plane in the horizontal direction, and the sum of the areas of the second micropore plane (7) and the third micropore plane (8) does not exceed 1/5 of the total plane area of the three-layer step plane in the horizontal direction; wherein the content of the first and second substances,
the centers of the first micropore plane (6), the second micropore plane (7) and the third micropore plane (8) are positioned in the same vertical direction; the thickness of the first micropore plane (6) is 25-80 mu m;
the glue is only coated on the surface of the second micropore plane (7); and the number of the first and second electrodes,
the anode gas diffusion layer and the cathode gas diffusion layer respectively comprise second frame films (9) which are positioned at the two side edges of the substrate layer-micropore layer connecting structure and used for fixing the substrate layer (4) and the micropore layer (5); the second frame film (9) on each side is bonded and fixed with the first frame film (10) of the five-in-one membrane electrode through high-viscosity glue.
Compared with the prior art, the invention can realize at least one of the following beneficial effects:
1. when the pressed gas diffusion layer is attached to the first frame membrane (10), the packaging strength between the gas diffusion layer and the five-in-one membrane electrode is enhanced, the stress concentration phenomenon is improved, and meanwhile, the contact resistance between the gas diffusion layer and the five-in-one membrane electrode cannot be increased due to pre-compression of the gas diffusion layer.
2. The microporous layer and the substrate layer of the gas diffusion layer are pre-pressed by the mould pressing plate (3), the microporous layer with a loose structure is pre-pressed, and the substrate layer is compressed, so that the bonding strength of the gas diffusion layer and the first frame membrane (10) is improved, and the stress concentration phenomenon is improved.
3. The second frame film (9) is added, and the stability of the whole structure is improved.
In another aspect, embodiments of the present invention further provide a gas diffusion layer for a fuel cell, which is prepared by the above preparation method and used as an anode gas diffusion layer or a cathode gas diffusion layer.
In addition, the embodiment of the invention also provides a full-size membrane electrode for a fuel cell, which comprises the anode gas diffusion layer, the cathode gas diffusion layer and a five-in-one membrane electrode; the anode gas diffusion layer, the five-in-one membrane electrode and the cathode gas diffusion layer are sequentially connected, and the connecting parts are bonded and fixed through glue; wherein the content of the first and second substances,
during preparation, firstly, a cathode catalyst layer (13) and an anode catalyst layer (12) are respectively transferred onto a proton exchange membrane (11) through coating, a first frame membrane (10) is coated on the two side edges of a cathode catalyst layer-proton exchange membrane-anode catalyst layer connecting structure to fix the cathode catalyst layer (13), the proton exchange membrane (11) and the anode catalyst layer (12) to obtain the five-in-one membrane electrode, and then the five-in-one membrane electrode is respectively bonded and fixed with a cathode gas diffusion layer and an anode gas diffusion layer.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the disclosure, nor is it intended to be used to limit the scope of the disclosure.
Drawings
The foregoing and other objects, features and advantages of the disclosure will be apparent from the following more particular descriptions of exemplary embodiments of the disclosure as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the disclosure.
Fig. 1 is a schematic view showing the composition of a method for producing a gas diffusion layer for a fuel cell in example 1;
FIG. 2 is a schematic diagram showing the preparation process of the anode gas diffusion layer or the cathode diffusion layer using low viscosity glue in example 2;
FIG. 3 is a schematic diagram showing the preparation process of the anode gas diffusion layer or the cathode diffusion layer using the high-viscosity glue in example 2;
FIG. 4 is a schematic view showing the structure of an anode gas diffusion layer or a cathode diffusion layer in a membrane electrode according to example 3;
FIG. 5 is a schematic view showing the structure of a membrane electrode for a fuel cell according to example 4;
FIG. 6 is a schematic view showing the structure of a membrane electrode for a fuel cell in example 4;
fig. 7 is a schematic diagram showing the structure of the anode gas diffusion layer or the cathode diffusion layer of example 4.
Reference numerals:
1-substrate layer (before lamination); 2-microporous layer (before lamination); 3-moulding a plate; 4-laminating the base layer; 5-laminating the microporous layer; 6-a first micropore plane; 7-a second micropore plane; 8-a third micropore plane; 9-a second border film; 10-a first border film; 11-a proton exchange membrane; 12-anode catalyst layer; 13-cathode catalyst layer.
Detailed Description
Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The term "include" and variations thereof as used herein is meant to be inclusive in an open-ended manner, i.e., "including but not limited to". The term "or" means "and/or" unless specifically stated otherwise. The term "based on" means "based at least in part on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first," "second," and the like may refer to different or the same object. Other explicit and implicit definitions are also possible below.
Example 1
In one embodiment of the present invention, a method for preparing a gas diffusion layer for a fuel cell is disclosed, as shown in fig. 1, including the steps of:
s1, preparing a microporous layer 2 with uniform thickness on a substrate layer 1 to obtain an initial gas diffusion layer;
s2, after the initial gas diffusion layer is placed on a smooth horizontal plane and fixed, applying a pressure of 0.1-1.0 MPa vertically upwards or downwards to the initial gas diffusion layerFLaminating and bonding the microporous layer 2 and the substrate layer 1 until the stress concentration phenomenon is eliminated, and forming a laminated substrate layer 4 and a laminated microporous layer 5; in an exemplary manner, the first and second electrodes are,F=0.5 MPa；
and S3, uniformly coating the glue on the top edge of the laminated microporous layer 5 to finish the preparation of the gas diffusion layer for the fuel cell.
It is worth mentioning that the pressure isFThe specific value of (A) depends on the application strip of the glueThe component and the packaging force of the gas diffusion layer under the condition of keeping the membrane electrode performance can be calibrated according to a laboratory
F=g（T，S，Q，F Package with a metal layer ）
In the formula (I), the compound is shown in the specification,Tit is the temperature of the gas that is,Sis composed ofHumidity，QIs the amount of intake air,Fto maintain the packing force of the gas diffusion layer under the membrane electrode performance.
Compared with the prior art, the embodiment provides a preparation method for pre-pressing the gas diffusion layer to eliminate the stress concentration phenomenon, so as to improve the packaging qualification rate of the gas diffusion layer in the full-size membrane electrode. Under a small pressure, the microporous layer 2 with a loose structure in the initial gas diffusion layer is pressed and the substrate layer 1 is compressed, the integrity and the cohesiveness of the substrate layer 4 and the microporous layer 5 after being pressed are improved, and then the glue is coated on the top edge of the microporous layer 5 after being pressed, so that when the gas diffusion layer is bonded with the five-in-one membrane electrode, the packaging strength between the gas diffusion layer and the five-in-one membrane electrode is enhanced, and the stress concentration phenomenon is improved.
Example 2
The material of the substrate layer 1 may be any one of carbon paper, carbon cloth, porous ceramic plate, bamboo fiber woven plate, carbon felt, metal mesh, metal felt, metal foam, and porous fiber membrane, which is modified based on the method of example 1.
Preferably, the material of the microporous layer 2 includes at least one of an elastic carbon nanotube porous layer, an elastic graphene porous layer, an elastic carbon fiber porous layer, an elastic carbon felt, or an elastic carbon paper.
Preferably, the step S1 further includes:
s11, preparing a substrate layer 1 with a porous gas transmission channel;
s12, uniformly coating the slurry of the microporous layer 2 on the upper surface of the substrate layer 1;
s13, connecting a vacuum pump with the substrate layer coated with the slurry of the microporous layer 2, vacuumizing, performing adsorption pre-infiltration treatment, and then sequentially drying and sintering; wherein the drying temperature is 60-80 ℃, the drying time is 6-24 h, the sintering temperature is 250-400 ℃, and the sintering time is 60-110 min;
s14, pre-pressing the sintered base layer coated with the microporous layer slurry to obtain the initial gas diffusion layer.
Preferably, the thickness of the substrate layer 1 is 90-200 μm, and in addition to the end points, 100 μm, 150 μm and 190 μm can be selected. The coating thickness of the microporous layer slurry is 30-80 μm, and for example, the coating thickness can be 40 μm, 50 μm, 60 μm and 70 μm besides the end points.
Preferably, the step S2 further includes:
s21, uniformly distributing a plurality of stress sensors at the bottom of a substrate layer of the initial gas diffusion layer;
s22, placing the initial gas diffusion layer provided with the stress sensor on a smooth horizontal plane for fixing, so that the microporous layer 1 faces upwards;
s23, applying downward pressure of 0.1-1.0 MPa (exemplarily, 0.6 MPa) for 6-20 s to the initial gas diffusion layer through the mould pressing plate 3 to press and bond the microporous layer 2 and the substrate layer 1;
s24, in the pressing process, monitoring stress data acquired by each stress sensor until all the stress data exceed a set value and the variance of all the stress data is lower than a preset variance upper limit, judging that the stress concentration phenomenon is eliminated, stopping the pressing, and removing the stress sensors to obtain the pressed microporous layer 5 and the pressed substrate layer 4.
Preferably, the bottom of the mold pressing plate 3 is a smooth horizontal plane or a plane with multiple steps (also called a multi-step plane), as shown in fig. 2 to 3.
Preferably, for low-tack glues, a molded plate 3 with a smooth horizontal surface at the bottom is used, exemplarily a two-component reactive polyurethane adhesive, resulting in a laminated microporous layer 5 with a smooth horizontal surface on the side facing away from the laminated substrate layer 4, as shown in fig. 2. And for high-viscosity glue (such as single-component glue and double-component glue with poor permeability), a mould pressing plate 3 with a plurality of layers of stepped planes at the bottom is adopted, the number of steps is more than or equal to 2, and illustratively, AB glue and acrylic acid structural glue/anaerobic glue are adopted to obtain a laminated microporous layer 5 with a plurality of layers of stepped planes on the surface away from the substrate layer 4. The stepped height enables the five-in-one membrane electrode to be fully contacted with the gas diffusion layer, and the contact resistance between the five-in-one membrane electrode and the gas diffusion layer is reduced. In general, the higher the ambient temperature, the lower the glue viscosity, and the lower the ambient temperature, the higher the glue viscosity.
Preferably, the above pressureFObtained by the following formula
F=f（T，S，Q max ，Q min ，F Packaging force ）
In the formula (I), the compound is shown in the specification,Tis the preset temperature of the air entering the stack when the fuel cell works,Sthe preset humidity of the air entering the stack when the fuel cell works,Q max the preset maximum ventilation quantity of the stack air when the fuel cell works,Q min a preset minimum ventilation of stack air during fuel cell operation,F packaging force To maintain a minimum packing force of the gas diffusion layer under membrane electrode performance,f() The fitting function can be obtained through laboratory calibration, test data are obtained through accelerated tests, and the optimization condition is that the service time is longest.
Preferably, a pressure having a downward value of 0.5 to 0.9 MPa and a pressing time of 10 to 15 s is applied to the initial gas diffusion layer through the mold plate 3 having three stepped planes at the bottom thereofFThe microporous layer 2 and the substrate layer 1 are pressed and bonded, three stepped planes are formed on the top of the microporous layer 5 after pressing, and the three horizontal planes formed in sequence from top to bottom are a first microporous plane 6, a second microporous plane 7 and a third microporous plane 8. Wherein the area of the first micropore plane 6 is equal to or greater than 4/5 of the total plane area of the three-layer step planes in the horizontal direction, and the sum of the areas of the second micropore plane 7 and the third micropore plane 8 does not exceed 1/5 of the total plane area of the three-layer step planes in the horizontal direction, as shown in fig. 3.
The first microwell plane 6 may be a circular plane, a rectangular plane, or other plane. The second micropore plane 7 and the third micropore plane 8 can adopt annular planes or other planes with the same height. The centers of the first micropore plane 6, the second micropore plane 7 and the third micropore plane 8 are positioned in the same vertical direction. The thickness of the first microporous plane 6 (the distance between the first microporous plane and the bottom of the microporous layer) is 25 to 80 μm, and for example, 40 μm, 50 μm, 60 μm, or 70 μm may be selected in addition to the end points.
Preferably, the glue is applied only to the surface of the second microporous plane 7.
Preferably, the method further comprises the steps of:
and S25, arranging second frame membranes 9 for fixing the substrate layer 4 and the microporous layer 5 on the edges of two sides of the substrate layer-microporous layer connecting structure.
S26, coating high-viscosity glue on the surface of the second frame membrane 9 on each side, so that the second frame membrane 9 on each side is bonded and fixed with the first frame membrane 10 of the five-in-one membrane electrode through the high-viscosity glue.
In the implementation process, tests prove that the membrane electrode does not fall off after 3000 times, 6000 times and 9000 times of oxidative corrosion in a galvanic pile as shown in fig. 4, and the structural stability of the membrane electrode is greatly improved compared with that of a full-size membrane electrode in the prior art.
Compared with the method of embodiment 1, the method provided by the embodiment has the following beneficial effects:
1. when the pressed gas diffusion layer is attached to the first frame membrane 10, the packaging strength between the gas diffusion layer and the five-in-one membrane electrode is enhanced, the stress concentration phenomenon is improved, and meanwhile, the contact resistance between the gas diffusion layer and the five-in-one membrane electrode cannot be increased due to the pre-compression of the gas diffusion layer.
2. The microporous layer and the substrate layer of the gas diffusion layer are pre-pressed by using the mold pressing plate 3, the microporous layer with a loose structure is pre-pressed, and the substrate layer is compressed, so that the bonding strength between the gas diffusion layer and the first frame membrane 10 is improved, and the stress concentration phenomenon is improved.
3. The second frame film 9 is added, and the stability of the whole structure is improved.
Example 3
The invention also discloses a gas diffusion layer for a fuel cell, which is prepared by the preparation method of the embodiment 1 or 2 and is used as an anode gas diffusion layer or a cathode gas diffusion layer, and the gas diffusion layer for the fuel cell is shown in figure 4.
Example 4
The invention also discloses a full-size membrane electrode for a fuel cell, which comprises an anode gas diffusion layer, a cathode gas diffusion layer and a five-in-one membrane electrode in embodiment 3; the anode gas diffusion layer, the five-in-one membrane electrode and the cathode gas diffusion layer are sequentially connected, and the connecting parts are bonded and fixed through glue, as shown in figures 4-5.
During preparation, firstly, the cathode catalyst layer 13 and the anode catalyst layer 12 are respectively transferred onto the proton exchange membrane 11 by coating, the first frame membrane 10 is coated on the two side edges of the cathode catalyst layer-proton exchange membrane-anode catalyst layer connecting structure to fix the cathode catalyst layer 13, the proton exchange membrane 11 and the anode catalyst layer 12, so as to obtain the required five-in-one membrane electrode, and then the five-in-one membrane electrode is respectively bonded and fixed with the cathode gas diffusion layer and the anode gas diffusion layer by glue (by glue coated on the edge of the microporous layer 5, or by glue coated on the edge of the microporous layer 5 and the surface of the second frame membrane 9).
The anode gas diffusion layer and the cathode gas diffusion layer are of the same structure, and each of the anode gas diffusion layer and the cathode gas diffusion layer comprises a substrate layer-microporous layer connecting structure and a second frame membrane 9, wherein the substrate layer-microporous layer connecting structure is subjected to a pressing process with a pressure of 0.1-1.0 MPa to bond the substrate layer 4 and the microporous layer 5 and eliminate the internal stress concentration phenomenon, and the second frame membrane 9 is located at the edge of the substrate layer-microporous layer connecting structure and is used for fixing the substrate layer 4 and the microporous layer 5, as shown in FIGS. 6-7.
Preferably, the cathode catalyst layer 13, the proton exchange membrane 11, the anode catalyst layer 12, and the substrate layer 4 all adopt a membrane structure of uniform thickness.
The thickness of the anode catalyst layer is preferably 4 to 11 μm, and illustratively, 4 μm, 6 μm, 8 μm, or the like may be selected in addition to the endpoints.
Preferably, the thickness of the proton exchange membrane 11 is 5 to 16 μm, and illustratively, 8 μm, 12 μm, 15 μm, and the like may be selected besides the end points.
The thickness of the cathode catalyst layer is preferably 5 to 13 μm, and may be, for example, 6 μm, 8 μm, 10 μm, or the like, except for the end points. The cathode catalyst layer is thicker than the anode catalyst layer.
Preferably, the thicknesses of the anode gas diffusion layer and the cathode gas diffusion layer are respectively 160-250 μm.
In the anode gas diffusion layer and the cathode gas diffusion layer, the substrate layer 4 is preferably made of a substrate layer material which has porous gas transmission channels and is prepared through a pressing process. And the surface roughness of the micropore layer surface of the substrate layer-micropore layer connecting structure is less than or equal to 1 mu m, and the surface roughness of the substrate layer surface is 2-3 mu m.
In the anode gas diffusion layer and the cathode gas diffusion layer, the thickness of the base layer 4 is preferably 90 to 200 μm, and for example, 100 μm, 150 μm, and 190 μm may be selected besides the end points.
The thickness of the microporous layer 5 is 30 to 80 μm, and illustratively, 40 μm, 50 μm, 60 μm, and 70 μm may be selected in addition to the end points.
The surface shape and size of the first frame film 10 are matched with those of the connecting part of the second frame film 9.
The second frame film 9 and the first frame film 10 both adopt a high-compactness structure and have smooth connection surfaces. The membrane electrode structure for a fuel cell can be made more stable by bonding the second frame membrane 9 and the first frame membrane 10 in a pore-free structure.
The first frame membrane 10 is fixed on the edges of the cathode catalyst layer 13 and the anode catalyst layer 12, which are away from the side surface of the proton exchange membrane 11, respectively, by gluing. Glue is coated on the surfaces of the cathode catalyst layer 13 and the anode catalyst layer 12.
In the implementation process, tests prove that the membrane electrode does not fall off after being subjected to oxidative corrosion for 3000 times, 6000 times and 9000 times in a galvanic pile, and the structural stability of the membrane electrode is greatly improved compared with that of a full-size membrane electrode in the prior art.
Example 5
The invention also discloses a fuel cell stack device, which comprises a shell, the membrane electrode for the fuel cell, which is arranged in the shell and is described in the embodiment 1 or 2, a cathode gas flow passage and an anode gas flow passage.
Wherein, the shape and the size of the edge of the membrane electrode for the fuel cell are matched with the shape and the size of an installation part provided with the membrane electrode in the shell. The cathode gas flow channel and the anode gas flow channel are respectively arranged at two sides of the membrane electrode for the fuel cell, and the respective flow channel spaces are separated by the membrane electrode for the fuel cell.
The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles of the embodiments, the practical application, or improvements made to the prior art, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (10)

1. A method for preparing a gas diffusion layer for a fuel cell, comprising the steps of:
preparing a microporous layer (2) with uniform thickness on a substrate layer (1) to obtain an initial gas diffusion layer;
after the initial gas diffusion layer is placed on a smooth horizontal plane and fixed, applying pressure of 0.1-1.0 MPa vertically upwards or downwards to press and bond the microporous layer (2) and the substrate layer (1) until the stress concentration phenomenon is eliminated, and forming a pressed substrate layer (4) and a pressed microporous layer (5);
and uniformly coating the glue on the top edge of the laminated microporous layer (5) to finish the preparation of the gas diffusion layer for the fuel cell.
2. The method of manufacturing a gas diffusion layer for a fuel cell according to claim 1, wherein the material of the substrate layer (1) includes at least one of carbon paper, carbon cloth, porous ceramic plate, bamboo fibril woven plate, carbon felt, metal mesh, metal felt, metal foam, porous fiber membrane; and the number of the first and second electrodes,
the material of the microporous layer (2) comprises at least one of an elastic carbon nanotube porous layer, an elastic graphene porous layer, an elastic carbon fiber porous layer, an elastic carbon felt or elastic carbon paper.
3. The method for producing a gas diffusion layer for a fuel cell according to claim 1 or 2, wherein the step of producing a microporous layer (2) of uniform thickness on a substrate layer (1) to obtain an initial gas diffusion layer further comprises:
preparing a substrate layer (1) with porous gas transmission channels;
uniformly coating the microporous layer slurry on the upper surface of the substrate layer (1);
connecting a vacuum pump with the substrate layer coated with the microporous layer slurry, vacuumizing, performing adsorption pre-infiltration treatment, and then sequentially drying and sintering; wherein the drying temperature is 60-80 ℃, the drying time is 6-24 h, the sintering temperature is 250-400 ℃, and the sintering time is 60-110 min;
and pre-laminating the sintered substrate layer coated with the microporous layer slurry to obtain the initial gas diffusion layer.
4. The method for manufacturing a gas diffusion layer for a fuel cell according to claim 3, wherein the thickness of the base layer (1) is 90 to 200 μm; and the number of the first and second electrodes,
the coating thickness of the microporous layer slurry is 30-80 mu m.
5. The method for preparing a gas diffusion layer for a fuel cell according to claim 4, wherein the step of applying a pressure of 0.1 to 1.0 MPa vertically upward or downward to press and bond the microporous layer (2) and the substrate layer (1) until the stress concentration phenomenon is recognized to be eliminated after the initial gas diffusion layer is fixed on a smooth horizontal surface, further comprises:
uniformly distributing a plurality of stress sensors at the bottom of a substrate layer (1) of the initial gas diffusion layer;
placing the initial gas diffusion layer provided with the stress sensor on a smooth horizontal plane for fixing, so that the microporous layer (2) faces upwards;
applying downward pressure of 0.1-1.0 MPa to the initial gas diffusion layer for 6-20 s through the mould pressing plate (3)FSo as to press and bond the microporous layer (2) and the substrate layer (1);
and in the laminating process, monitoring stress data acquired by each stress sensor until all the stress data exceed a set value and the variance of all the stress data is lower than a preset variance upper limit, judging that the stress concentration phenomenon is eliminated, stopping laminating, and removing the stress sensors to obtain the laminated microporous layer (5) and the laminated substrate layer (4).
6. The method for manufacturing a gas diffusion layer for a fuel cell according to claim 5, wherein the bottom of the molded plate (3) is a smooth horizontal plane or a plane having a multi-step shape; wherein the content of the first and second substances,
for low-viscosity glue, adopting a mould pressing plate (3) with a smooth horizontal plane at the bottom to obtain a laminated microporous layer (5) with a smooth horizontal plane at the surface deviating from the laminated substrate layer (4); and the number of the first and second electrodes,
for the high-viscosity glue, a mould pressing plate (3) with a plurality of layers of stepped planes at the bottom is adopted, the number of steps is more than or equal to 2, and a laminated microporous layer (5) with a plurality of stepped planes on one surface departing from the laminated base layer (4) is obtained.
7. The method of preparing a gas diffusion layer for a fuel cell according to claim 6, wherein the pressure isFObtained by the following formula
F=f（T，S，Q max ，Q min ，F Packaging force ）
In the formula (I), the compound is shown in the specification,Tis the preset temperature of the air entering the stack when the fuel cell works,Sthe preset humidity of the stack air when the fuel cell works,Q max the preset maximum ventilation quantity of the stack air when the fuel cell works,Q min a preset minimum ventilation of stack air during fuel cell operation,F packaging force To maintain a minimum packing force of the gas diffusion layer under membrane electrode performance,f() Is a fitting function.
8. The method for manufacturing a gas diffusion layer for a fuel cell according to any one of claims 5 to 7, wherein a pressure having a downward value of 0.5 to 0.9 MPa and a pressing time of 10 to 15 s is applied to the initial gas diffusion layer by means of a press plate (3) having three stepped flat surfaces at the bottom thereofFLaminating and bonding the microporous layer (2) and the substrate layer (1), forming three stepped planes on the top of the laminated microporous layer (5), wherein the three planes formed from top to bottom are a first microporous plane (6), a second microporous plane (7) and a third microporous plane (8) in sequence; the area of the first micropore plane (6) exceeds 4/5 of the total plane area of the three-layer step plane in the horizontal direction, and the sum of the areas of the second micropore plane (7) and the third micropore plane (8) does not exceed 1/5 of the total plane area of the three-layer step plane in the horizontal direction; wherein the content of the first and second substances,
the centers of the first micropore plane (6), the second micropore plane (7) and the third micropore plane (8) are positioned in the same vertical direction; the thickness of the first micropore plane (6) is 25-80 mu m;
the glue is only coated on the surface of the second micropore plane (7); and also,
the anode gas diffusion layer and the cathode gas diffusion layer respectively comprise second frame membranes (9) which are positioned at two side edges of the base layer-microporous layer connecting structure and are used for fixing the base layer (4) and the microporous layer (5); the second frame film (9) on each side is bonded and fixed with the first frame film (10) of the five-in-one membrane electrode through high-viscosity glue.
9. A gas diffusion layer for a fuel cell, which is produced by the production method according to any one of claims 1 to 8, and which is used as an anode gas diffusion layer or a cathode gas diffusion layer.
10. A full-size membrane electrode for a fuel cell, comprising the anode gas diffusion layer, the cathode gas diffusion layer, and a penta-membrane electrode according to claim 9; the anode gas diffusion layer, the five-in-one membrane electrode and the cathode gas diffusion layer are sequentially connected, and the connecting parts are bonded and fixed through glue; wherein the content of the first and second substances,
during preparation, firstly, a cathode catalyst layer (13) and an anode catalyst layer (12) are respectively transferred onto a proton exchange membrane (11) through coating, a first frame membrane (10) is coated on the two side edges of a cathode catalyst layer-proton exchange membrane-anode catalyst layer connecting structure to fix the cathode catalyst layer (13), the proton exchange membrane (11) and the anode catalyst layer (12) to obtain the five-in-one membrane electrode, and then the five-in-one membrane electrode is respectively bonded and fixed with a cathode gas diffusion layer and an anode gas diffusion layer.
CN202210671469.2A 2022-06-15 2022-06-15 Membrane electrode for fuel cell, gas diffusion layer and preparation method thereof Pending CN115000443A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663211A (en) * 2022-11-11 2023-01-31 上海氢晨新能源科技有限公司 Gas diffusion layer and fuel cell

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115663211A (en) * 2022-11-11 2023-01-31 上海氢晨新能源科技有限公司 Gas diffusion layer and fuel cell
CN115663211B (en) * 2022-11-11 2023-09-29 上海氢晨新能源科技有限公司 Gas diffusion layer and fuel cell

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