Integrated Gas Diffusion Layer for Fuel Cell, Method for Manufacturing the Same, and Use Thereof

Abstract

The present application provides an integrated gas diffusion layer for a fuel cell, a method for manufacturing the same, and its use. The method for manufacturing the integrated gas diffusion layer includes the steps of integrating a flow field plate and a gas diffusion layer into an integrated structure, and forming a flow field structure having flow channels and ridges by etching or pressing the surface of the gas diffusion layer, thereby forming an integrated gas diffusion layer having the function of a flow field on the surface of the gas diffusion layer. According to the technical solution of the present application, by using methods such as laser engraving, machining, and mechanical pressing to engrave a structure having high-porosity flow channels and microchannel ridges on the surface of a conventional gas diffusion layer, the integration of the flow field plate and the gas diffusion layer is realized. The operation is rapid and simple, the processing cost is low, and the manufactured integrated gas diffusion layer has good water management ability and can transmit gas to the catalyst layer more quickly, thereby enabling the battery to have higher battery performance.

Description

Technical Field

[0001] This application is based on and claims priority to a Chinese patent application with the Chinese patent application number 202310684663.9, titled "Integrated Gas Diffusion Layer for Fuel Cells, Its Manufacturing Method and Use", filed on June 9, 2023.

[0002] (Technical Field) This application relates to the technical fields of energy and clean energy, and specifically relates to an integrated gas diffusion layer for fuel cells, its manufacturing method, and its use.

Background Art

[0003] Hydrogen, as a carbon-free energy medium, is widely used in fuel cells. Fuel cells can convert hydrogen into electrical energy, and have the characteristics of high efficiency, no pollution, and fast startup. Proton exchange membrane fuel cells (PEMFCs) have relatively high energy power and room temperature startup capabilities. Proton exchange membrane fuel cells have characteristics such as high efficiency, no pollution of the products, and can operate at low temperatures. They are regarded as one of the most promising fuel cells and have already been put into practical use in fuel cell vehicles and stationary fuel cells, etc.

[0004] However, due to the market requirements for new energy products, it has been determined that fuel cells need to obtain a smaller volume or mass, a lower manufacturing cost, and a higher output power as their development goals. Fuel cells in the prior art mainly consist of bipolar plates, gas diffusion layers, microporous layers, catalyst layers, and proton exchange membranes. Among them, the gas diffusion layer plays a role in transporting reactants and products, and plays an irreplaceable role in fuel cells. The gas diffusion layer is one of the core components of proton exchange membrane fuel cells, and the main roles it plays in the battery are (1) supporting the catalyst layer, (2) transporting the reaction gas to the catalyst layer to carry out an electrochemical reaction, and (3) discharging excess water outside the battery.

[0005] Currently, in the prior art, there are no significant structural differences in fuel cells due to their model numbers or manufacturers. To promote the weight reduction and large-scale application of fuel cells, it is necessary to reduce the mass of the fuel cell. Since the weight of the bipolar plate accounts for more than 80% of the mass of the fuel cell, it depends on whether the mass of the bipolar plate can be further reduced. In addition, the bipolar plate and the gas diffusion layer occupy most of the volume of the fuel cell, and their manufacturing costs account for more than 30% of the cost of the fuel cell. Therefore, by further reducing the volume and manufacturing costs of the bipolar plate and the gas diffusion layer, not only can the power density of the fuel cell be further increased, but also the volume and mass can be reduced, promoting the practical application of the fuel cell.

[0006] Conventional fuel cells use a combination of a bipolar plate and a gas diffusion layer to transport the reactants and products of the fuel cell. The bipolar plate distributes gas, drains water, and collects electricity, and the gas diffusion layer provides channels for gas reaction and channels for transporting water. Such a structure used in combination has the following problems. (1) The bipolar plate has a large mass and a more complex production process, so the production cost and power density of the fuel cell are limited. (2) Also, the contact area between the bipolar plate and the gas diffusion layer easily restricts the behavior of gas mass transfer, forming a weak mass transfer region for gas mass transfer, which is disadvantageous for the diffusion of gas to the catalyst layer, so the performance of the catalyst layer is limited. (3) Water easily accumulates in the contact area between the bipolar plate and the gas diffusion layer, preventing the movement of gas to the gas diffusion layer, being disadvantageous for the permeation of reactive gas, and further reducing the battery performance.

[0007] On the other hand, the conventional battery structure not only faces problems such as low specific power and high manufacturing cost, but also gas transport and flooding inside the battery are factors that keep the power density of the fuel cell low. To improve the power density of the fuel cell, it is necessary to further improve the structure of the pair of flow field plates and the gas diffusion layer.

[0008] J. Electrochem. Soc. 2019, 166, 3210-3215 discloses a method for manufacturing a gas diffusion layer having a flow channel structure using a mold pressing method, where the current collector plate is a flat metal plate, and the power density of the fuel cell is improved.

[0009] J. Power Sources. 2021, 515, 230636-230644 discloses a porous gas diffusion layer having a flow channel structure manufactured using a 3D printing method. The fuel cell can be assembled after high-temperature carbonization. Although the 3D printing technology is simpler than the mold pressing method technology, it has not played an obvious role in improving the battery performance.

[0010] Obviously, the prior art still lacks technical solutions that can realize the simplification of the fuel cell structure and the increase of the high power density.

[0011] Therefore, the present application provides an integrated gas diffusion layer, integrates the flow channel on the gas diffusion layer, manufactures an integrated gas diffusion layer having a special flow channel structure and microchannel ridges, and may use a flat metal plate or a graphite plate instead of the bipolar plate having a flow field. Such a structure can not only realize the reduction of the volume of the electrochemical energy conversion device, the improvement of the power density, and the improvement of the specific power, but also greatly reduce the volume of the fuel cell while ensuring the excellent gas transport performance and water transport performance of the fuel cell.

Summary of the Invention

Problems to be Solved by the Invention

[0012] In view of the above, in order to solve the above problems, the present application provides an integrated gas diffusion layer for a fuel cell, a manufacturing method thereof, and its use, and can efficiently manufacture an integrated gas diffusion layer having a special flow path structure and microchannel ridges, the process is simple, and the integrated gas diffusion layer can simultaneously exert the dual functions of a diffusion layer and a flow field, and can greatly reduce the mass / volume of an electrochemical energy conversion device that requires gas to participate in the reaction, and can improve the power density, specific power, and performance stability.

Means for Solving the Problem

[0013] In order to achieve the above object, the present application integrates a flow field plate and a diffusion layer into an integrated structure, and by etching or pressing the surface of the diffusion layer, a flow field structure having a flow path and a ridge is formed, so that the surface of the diffusion layer has the function of a flow field, and an integrated gas diffusion layer for a fuel cell is provided, which forms the integrated gas diffusion layer.

[0014] Preferably, the flow field structure includes a flow path having a porous structure and a microchannel ridge.

[0015] Preferably, the flow field structure etches the surface layer of the gas diffusion layer by engraving or machining to form a flow field having a flow path with a porous structure and a microchannel ridge, and the base layer of the gas diffusion layer is not etched, and by maintaining the structure of the gas diffusion layer, the gas diffusion layer and the flow field are integrated into an integrated structure, and an integrated gas diffusion layer having both the functions of the gas diffusion layer and the flow field is formed.

[0016] Preferably, the etching method includes laser engraving.

[0017] Preferably, the pressing method includes either machining or mechanical pressing.

[0018] Preferably, the flow channel structure includes any one of a serpentine flow field, a comb-shaped flow field, and a parallel flow field.

[0019] Preferably, in the flow field structure, the microchannel ridge has a thickness of 370 μm and a width of 1 mm, and the flow channel has a depth of 200 μm and a width of 1 mm.

[0020] Preferably, the material of the gas diffusion layer includes carbon paper manufactured by Toray Industries, Inc.

[0021] To achieve another object, the present application further provides a method for manufacturing an integrated gas diffusion layer for a fuel cell as described above, which designs different types of flow channel structures using software, introduces the designed flow channel structure into a laser marking machine or a machining device, and laser engraves carbon paper or presses it with a machining device to obtain an integrated gas diffusion layer having a flow channel structure, or manufactures a mold having the flow channel structure using a 3D printing method, places carbon paper on the mold and presses it to obtain an integrated gas diffusion layer of the flow channel structure.

[0022] Preferably, the integrated gas diffusion layer is manufactured by a laser marking machine, a milling machine or a sheet press.

[0023] Preferably, the software includes UG software.

[0024] Specifically, a commercial gas diffusion layer is selected, the gas diffusion layer is fixed to an adsorption platform, the adsorption platform is placed in the cavity of a laser marking machine, different types of flow channel structures are designed using software, the designed flow channel structure diagram is introduced into the laser marking machine, and different types of integrated gas diffusion layers are obtained by manufacturing according to the designed type of flow field.

[0025] Alternatively, commercial carbon paper is placed on a platform, and the carbon paper is pressed using a milling machine according to the designed flow channel model.

[0026] Alternatively, first print a mold with parallel flow channels using a 3D printer, and then place the mold on carbon paper and press it.

[0027] Assemble the integrated gas diffusion layer manufactured by the above technical solution and a flat metal plate or graphite plate to obtain a membrane electrode. Specifically, the membrane electrode assembly is assembled with an integrated GDL and includes a cathode, an anode, a catalyst coating film, a bipolar plate, and an integrated gas diffusion layer. Assemble the above assembly to obtain a membrane electrode.

[0028] Preferably, the cathode is an integrated GDL made of TGP-120, the anode is an integrated GDL made of TGP-090, the catalyst is JMHispec 9100 (55.5 - 58.5%), and the Pt loading amounts of the anode and cathode are 0.24 and 0.48 mg·cm -2 respectively, and the bipolar plate is a flat graphite plate or a graphite plate.

[0029] Enclose the above assembly in a battery case and assemble it into a fuel cell.

[0030] The peak power density of the battery manufactured under the condition of a back pressure of 0 kPa is 1.2 W / cm 2 or more, and when the back pressure rises to 50 kPa, the peak power density of the battery reaches 1.4 W / cm 2

[0031] It is obvious that the integrated gas diffusion layer according to the present application can play the roles of both the diffusion layer and the flow field, significantly reducing the mass / volume of the electrochemical energy conversion device in which the gas participates in the reaction, improving the power density, improving the stability, and significantly improving the specific power.

Advantages of the Invention

[0032] The beneficial technical effects obtained by the present application are as follows. 1. According to the technical solution of the present application, by using methods such as laser engraving, machining, and mechanical pressing to engrave a structure with high-porosity flow channels and microchannel ridges on the surface of the conventional gas diffusion layer, the integration of the flow field plate and the gas diffusion layer is realized, the operation is rapid and simple, the processing cost is low, and the manufactured integrated gas diffusion layer has good water management ability, can transfer gas to the catalyst layer more quickly, and thereby enables the battery to have higher battery performance.

[0033] 2. According to the technical solution of the present application, by integrating the flow field on the surface of the diffusion layer to form an integrated structure and using a flat metal plate or graphite plate as the bipolar plate, the thickness and mass of the fuel cell can be significantly reduced, and not only can the reduction of the volume of the electrochemical energy conversion device, the improvement of the power density, and the improvement of the specific power be realized, but also while ensuring that the fuel cell has excellent gas transport performance and water transport performance, the volume of the fuel cell can be significantly reduced.

[0034] 3. According to the technical solution of the present application, it has excellent versatility, and parameters such as the width of the flow channel and the type of the flow channel can be accurately set and controlled by software. While quickly manufacturing the integrated gas diffusion layer, the manufactured flow channel has a relatively high porosity, there are a large number of microchannels inside the ridge of the flow channel, and it has the advantages of simple process, simple raw materials, and low energy consumption, and is suitable for mass production and popularization.

[0035] 4. The integrated gas diffusion layer manufactured by adopting the technical solution of the present application does not require a conventional flow field plate when assembling the battery, can be assembled only with a flat metal plate or a graphite plate, and has excellent water management ability, and is suitable for electrochemical energy conversion devices that require the participation of gas or liquid.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3a

Figure 3b

Figure 3c

Figure 3d

Figure 4a

Figure 4b

Figure 4c

Figure 5a

Figure 5b

Figure 5c

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0037] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, hereinafter, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings of the present application. However, it is obvious that the described embodiments are only some embodiments of the present application and not all embodiments.

[0038] The present application provides an integrated gas diffusion layer for a fuel cell, which integrates a flow field plate and a diffusion layer into an integrated structure, and forms a flow field structure having flow paths and ridges by etching or pressing the surface of the gas diffusion layer, so as to make the surface of the diffusion layer have the function of the flow field and form an integrated gas diffusion layer.

[0039] Furthermore, the flow path has a porous structure, the ridge has a microchannel structure, and the porous structure and the microchannel structure constitute the flow field structure.

[0040] Furthermore, the flow field structure is obtained by etching the surface layer of the gas diffusion layer by engraving or machining, and the base layer of the gas diffusion layer is not etched or pressed, and by maintaining the structure of the gas diffusion layer, the gas diffusion layer and the flow field are integrated into an integrated structure to form an integrated gas diffusion layer having both the functions of the gas diffusion layer and the flow field.

[0041] Preferably, as the material of the gas diffusion layer, carbon paper or other materials that can realize the same function as carbon paper and can form a flow field structure by etching or pressing can be selected. Preferably, Toray carbon paper can be selected.

[0042] In some preferred embodiments, it includes, but is not limited to, TGP-120 or TGP-090 manufactured by Toray Industries, Inc.

[0043] Specifically, the manufacturing steps of the integrated gas diffusion layer are as follows. Fix a commercial gas diffusion layer to the adsorption platform, and place the adsorption platform in the cavity of a laser marking machine capable of manufacturing an integrated gas diffusion layer with different channel widths and channel depths. Software can be used to design flow fields with different channel widths and different types of flow fields such as serpentine flow fields, comb-shaped flow fields, and parallel flow fields.

[0044] Specifically, with UG software, design flow field structures with different channel widths (0.1 - 2 mm) and different types of flow field structures such as serpentine flow fields, comb-shaped flow fields, parallel flow fields, and special-shaped flow fields. Introduce the designed channel structure diagram into the laser marking machine and perform laser engraving using the laser marking machine to manufacture an integrated gas diffusion layer with different channel widths. The channel depth can be controlled by the number of etching times by the laser marking machine (the depth is 200 μm).

[0045] Hereinafter, specific examples will be used to further detail the technical solution of the present application, apply the manufactured gas diffusion layer to the manufacture of fuel cells, and test its performance.

[0046] (Example 1) In this example, a commercial gas diffusion layer was used as the raw material, and a laser marking machine was used to laser engrave flow fields with different channel widths and different types of flow fields on the surface of the commercial gas diffusion layer.

[0047] Specifically, the manufacturing steps of the integrated gas diffusion layer include the following steps. A commercial gas diffusion layer (carbon paper manufactured by Toray Industries, Inc., model number: TGP-120) was fixed to the adsorption platform, and the adsorption platform was placed in the cavity of a laser marking machine (EP-15-THG). By adjusting the current (5 A) and the number of markings (50 times) of the laser marking machine, the intensity of laser engraving was changed, and the parameters of the flow field by laser engraving were adjusted.

[0048] UG software was used to design different types of flow field structures with a channel width of 1 mm. The designed channel structure diagrams were introduced into the laser marking machine, and laser engraving was performed using the laser marking machine with the etching times set to 50 times and the etching depth set to 200 μm, to manufacture an integrated gas diffusion layer with a serpentine flow field, a comb-shaped flow field, a parallel flow field, or a special-shaped flow field. Also, with UG software, it is possible to design flow fields with different channel widths (0.1 - 2 mm), and by adjusting the etching times, an integrated gas diffusion layer with different channel widths and different channel depths can be obtained.

[0049] Referring to Figure 1, according to the flowchart for manufacturing the parallel flow field according to this embodiment, the surface of the commercial gas diffusion layer was laser engraved using laser engraving technology, and based on the parallel flow field with the channel width and depth preset by the software, a flow field with parallel channels can be obtained.

[0050] (Example 2) In this example, a machining method for manufacturing an integrated carbon paper with a channel structure was adopted, specifically including the following.

[0051] Commercial carbon paper (TGP-120) was placed on a three-dimensional platform, and using a milling machine (XK7113C manufactured by Haomai Co., Ltd.), pressing was performed according to the designed channel model, and by setting the cutting depth of the milling machine to 0.1 mm, an integrated carbon paper with a channel structure can be obtained.

[0052] (Example 3) In this example, for the designed flow channel structure, a mold having the flow channel structure was processed with a 3D printer by referring to FIG. 7 and using a mold having parallel flow channels with a flow channel width of 0.5 mm to 2 mm printed by a 3D printer. Then, carbon paper (TGP-120) was placed on a sheet press machine (model number: BL-6170-C-10T), the manufactured mold was placed on the carbon paper, and by pressing at a pressure of 1 MPa, as shown in FIG. 8, an integrated carbon paper having the flow channel structure was obtained, including manufacturing an integrated carbon paper having the flow channel structure by a mechanical pressing method.

[0053] (Comparative Example 1) In this comparative example, it is different from Example 1 in that a conventional flow channel plate and a commercial gas diffusion layer are directly adopted instead of an integrated gas diffusion layer for battery assembly.

[0054] (Battery Assembly) The battery is assembled using the gas diffusion layers of the above examples and comparative examples. The manufacturing method of the membrane electrode assembly (MEA) is such that the cathode is an integrated GDL manufactured with TGP-120, the anode is an integrated GDL manufactured with TGP-090, the catalyst coated membrane (CCM) is manufactured by Suzhou Shengnuonuo Co., Ltd., China, the catalyst is JM Hispec 9100 (55.5 - 58.5%), and the Pt loadings of the anode and cathode are 0.24 and 0.48 mg·cm -2 respectively, and it is assembled from the integrated GDL.

[0055] The bipolar plate is a flat graphite plate.

[0056] The membrane electrode assembly, the bipolar plate, and the gas diffusion layer were enclosed in a battery case to assemble the battery.

[0057] (Performance Tests of Gas Diffusion Layer and Fuel Cell) 1. Morphology of Gas Diffusion Layer The surface and cross-section of the integrated gas diffusion layer were observed with a scanning electron microscope to obtain the structural and topographical information of the integrated gas diffusion layer, and the uniformity and continuity of the fabricated flow field (scanning electron microscope image of the surface) and the depth of the flow field (scanning electron microscope image of the cross-section) were observed.

[0058] 2. Test method for water transport capacity Water transport capacity plays an important role in improving the performance of the battery. During the operation of the fuel cell, the discharge of water in the battery has a great impact on the battery performance. If the water generated in the battery is not discharged in a timely manner, the diffusion of gas through the flow path to the diffusion layer will be greatly affected, and the battery will show serious concentration polarization.

[0059] In this application, by comparing the drainage time under the same mass, the drainage capacities of the commercial gas diffusion layer and the integrated gas diffusion layer are compared.

[0060] In this application, a self-made water discharge device was used to test the water transport capacity. Referring to Fig. 6, a schematic diagram of the structure of the water discharge device is shown. A certain mass of water was dropped onto the filter paper to wet the filter paper. The integrated gas diffusion layer and the wet filter paper were assembled, and after weighing the mass, they were placed in a jig and fixed. The jig was assembled from two removable transparent PC boards. Here, the upper PC board was provided with an air inlet and an air outlet. Air at 1 L / min was introduced from the air inlet, and the mass was weighed and recorded every 5 minutes, and the drainage rate curve was plotted.

[0061] The specific test steps include the following. (1) Fix the gas diffusion layer with dimensions of 1 cm × 5 cm and the filter paper containing 25 mg of water in the jig, connect the device, and weigh the total mass of the device. (2) Start the air pump to let the gas with a predetermined flow rate (1 times, 1.5 times, 2 times the theoretical gas flow rate) flow out from the air pump, enter from the inlet of the jig, and flow out from the outlet of the jig, and weigh the mass of the device every 5 - 20 minutes. (3) Record at least 5 points for each experiment, fit the curve, and obtain the water loss rate curve.

[0062] 3. Method for testing the performance of the battery The performance of the fuel cell was tested by a fuel cell test system. The polarization curve of the cell was tested by linear voltammetry at a temperature of 80°C, a humidity of 80%, and a pressure of 0 - 200 kPa, and the power curve of the cell was calculated. The flow rate of hydrogen gas was 0.5 L min -1 , and the flow rate of air was 2 L min -1 .

[0063] (Characteristic Evaluation and Analysis of Structure and Performance) 1. Characteristic Evaluation of Structure: The surface and cross-section of the integrated gas diffusion layer manufactured in this example were observed with a scanning electron microscope to obtain the structure and topography information of the integrated gas diffusion layer. Specifically, referring to FIGS. 2 and 3a - 3d, the uniformity and continuity of the flow field (scanning electron microscope image of the surface), and the depth of the flow field (scanning electron microscope image of the cross-section) were observed.

[0064] FIG. 2 is an SEM image when commercial carbon paper is used in Example 1 without laser engraving.

[0065] FIG. 3a shows the integrated gas diffusion layer manufactured by the laser engraving method in Example 1. Referring to the SEM image after etching on the left side of the mp red line in the figure, the original structure of the gas diffusion layer after etching was destroyed and formed. Compared with the unetched part on the right side, the right side maintained the original pore structure and functioned as a gas diffusion layer.

[0066] Referring to FIG. 3b, the unengraved part of the integrated gas diffusion layer in Example 1 maintains the form of the original gas diffusion layer. Therefore, the flow path after engraving has a richer porous structure and has a clear flow path structure as shown in the figure, with a flow path width of 1 mm, a depth of 200 μm, a flow path ridge width of 1 mm, and a thickness of 370 μm.

[0067] Furthermore, referring to FIG. 3c, it was found that both the flow path and the ridge of the integrated gas diffusion layer have a porous structure.

[0068] Referring to FIG. 3d, rich microchannels are formed inside the ridge of the integrated gas diffusion layer.

[0069] 2. Characteristics Evaluation of Water Transport Capacity When comparing the water transport capacity of the integrated gas diffusion layer manufactured in this example with that of the conventional flow field, referring to FIGS. 3a to 3b, when comparing the drainage rates of the integrated gas diffusion layer manufactured in Example 1 and the conventional flow field under gas flows with various stoichiometric ratios, as can be seen from the figures, the integrated gas diffusion layer is twice the gas-water drainage rate of the conventional flow field under the gas flow with the same stoichiometric ratio, indicating that the integrated gas diffusion layer manufactured in Example 1 has a better water management ability.

[0070] Specifically, as shown in FIG. 4a, when the introduced gas (gas water) is the same as the theoretical value, the drainage rate of the integrated gas diffusion layer is 2.17 times that of the conventional flow field. As shown in FIG. 4b, when the introduced gas is 1.5 times the theoretical value, the drainage rate of the integrated gas diffusion layer is 2.07 times that of the conventional flow field. As shown in FIG. 4c, when the introduced gas is twice the theoretical value, the drainage rate of the integrated gas diffusion layer is twice that of the conventional flow field. Thus, it is obvious that increasing the gas flow speeds up the discharge of water, but the integrated gas diffusion layer manufactured using Example 1 has good drainage performance even under low gas flow.

[0071] 3. Characteristics Evaluation of Battery Performance FIGS. 5a to 5c are comparison diagrams of the battery performance and maximum power density of the integrated gas diffusion layer manufactured in Example 1 and the commercial gas diffusion layer at various back pressures.

[0072] Referring to FIG. 5a, as a result of the test, even when the back pressure is 0 kPa, the integrated gas diffusion layer has excellent performance. When the back pressure rises to 50 kPa, the battery performance reaches 1.4 W / cm 2 It can be seen that the battery performance does not increase significantly even if the back pressure continues to increase, indicating that the integrated gas diffusion layer can achieve good battery performance at low back pressure.

[0073] Referring to FIG. 5b, for the commercial gas diffusion layer, as the back pressure increases, the battery performance gradually improves, but all are at a low level.

[0074] Referring to FIG. 5c, it is a comparison of the maximum peak power density between the integrated gas diffusion layer and the commercial gas diffusion layer. As can be seen from the figure, the integrated gas diffusion layer clearly rises more than the commercial gas diffusion layer at the same back pressure, reaching a maximum of 0.47 W / cm 2 and increasing to that value.

[0075] From the above, according to the integrated gas diffusion layer manufactured in the present application, the integrated gas diffusion layer manufactured by methods such as laser engraving, machining, and mechanical pressing can retain the structure at the bottom after destroying the surface structure of the original commercially available gas diffusion layer and continue to play the role of a gas diffusion layer in actual use. On the other hand, a new channel structure is formed on the surface of the original gas diffusion layer by methods such as laser engraving or pressing, and the actually required flow channel structure can be obtained according to the setting. Moreover, both the flow channels and the ridges in the flow channel structure include a porous structure, and there are rich microchannels inside the ridges. Therefore, the function of the flow field plate can be fully exerted, and thereby, the dual functions of the gas diffusion layer and the flow field plate can be realized.

[0076] The above are only preferred embodiments of the present application and do not limit the protection scope of the present application. The present application can be variously modified and changed for those skilled in the art. All substitutions, modifications, replacements, integrations, and parameter changes to these embodiments within the spirit and principle scope of the present application, as long as they can achieve the same function as the conventional ones, are included in the protection scope of the present application.

[0077] (Appendix) (Appendix 1) An integrated gas diffusion layer for a fuel cell, comprising integrating the flow field plate and the diffusion layer into an integrated structure, and by etching or pressing the surface of the diffusion layer to form a flow field structure having flow channels and ridges, thereby endowing the surface of the diffusion layer with the function of the flow field to form the integrated gas diffusion layer for the fuel cell.

[0078] (Appendix 2) The flow path has a porous structure, the ridge has a microchannel structure, and the porous structure and the microchannel structure constitute the flow field structure, the flow field structure is obtained by etching the surface layer of the gas diffusion layer by engraving or machining, and the base layer of the gas diffusion layer is not etched or pressed, and by maintaining the structure of the gas diffusion layer, the gas diffusion layer and the flow field are integrated into an integral structure to form an integrated gas diffusion layer having both functions of the gas diffusion layer and the flow field. The integrated gas diffusion layer for a fuel cell according to Appendix 1, characterized in that.

[0079] (Appendix 3) In the flow field structure, after etching or pressing the gas diffusion layer, a flow path structure is formed on the surface of the gas diffusion layer, and the unetched portion becomes the ridge of the flow path, the thickness of the ridge is the same as the thickness of the unetched portion of the gas diffusion layer, and / or the thickness of the ridge is 370 μm or less, the width of the flow path is 0.1 to 2 mm, and the flow path formed by the etching has a depth of 10 to 200 μm and a width of 0.1 to 2 mm. The integrated gas diffusion layer for a fuel cell according to Appendix 2, characterized in that.

[0080] (Appendix 4) The method of the etching includes laser engraving, and / or the method of the pressing includes either machining or mechanical pressing, and / or the flow path structure includes any one of a serpentine flow field, a comb-shaped flow field, and a parallel flow field. The integrated gas diffusion layer for a fuel cell according to any one of Appendices 1 to 3, characterized in that.

[0081] (Appendix 5) The material of the gas diffusion layer includes carbon paper manufactured by Toray Industries, Inc. The integrated gas diffusion layer for a fuel cell according to Appendix 4, characterized in that.

[0082] (Appendix 6) Design different types of flow channel structures using software, introduce the designed flow channel structure into a laser marking machine or a machining device, press carbon paper with a laser engraving or machining device to obtain an integrated gas diffusion layer having the flow channel structure, or manufacture a mold having the flow channel structure using a 3D printing method, place carbon paper on the mold and press it to obtain the integrated gas diffusion layer of the flow channel structure. And / or, the integrated gas diffusion layer is manufactured by a laser marking machine, a milling machine or a sheet press machine. And / or, the software includes UG software, and is characterized in that it is a method for manufacturing an integrated gas diffusion layer for a fuel cell according to any one of Appendices 1 to 5.

[0083] (Appendix 7) A membrane electrode for a fuel cell provided with the integrated gas diffusion layer according to any one of Appendices 1 to 5, which is obtained by performing an integrated GDL assembly on the integrated gas diffusion layer and a bipolar plate, and the bipolar plate is a flat metal plate or a graphite plate.

[0084] (Appendix 8) A fuel cell provided with the integrated gas diffusion layer according to any one of Appendices 1 to 5, or the membrane electrode according to Appendix 7.

[0085] (Appendix 9) The peak power density of the battery under the condition of a back pressure of 0 kPa is 1.2 W / cm 2 or more, and when the back pressure rises to 50 kPa, the peak power density of the battery reaches 1.4 W / cm 2 The fuel cell according to Appendix 8, characterized in that it reaches.

[0086] (Appendix 10) Use of the integrated gas diffusion layer according to any one of Appendices 1 to 5 in an energy conversion device.

Claims

1. An integrated gas diffusion layer for a fuel cell, wherein a flow field plate and a diffusion layer are integrated into an integral structure, and by etching or pressing the surface of the diffusion layer, a flow field structure having flow channels and ridges is formed, thereby imparting the function of a flow field to the surface of the diffusion layer to form the integrated gas diffusion layer for a fuel cell.

2. The flow channels have a porous structure, the ridges have a microchannel structure, and the porous structure and the microchannel structure constitute the flow field structure, the flow field structure is obtained by etching the surface layer of the gas diffusion layer by engraving or machining, and the base layer of the gas diffusion layer is not etched or pressed, and by maintaining the structure of the gas diffusion layer, the gas diffusion layer and the flow field are integrated into an integral structure to form an integrated gas diffusion layer having both the functions of a gas diffusion layer and a flow field. The integrated gas diffusion layer for a fuel cell according to claim 1, characterized in that.

3. In the flow field structure, after etching or pressing the gas diffusion layer, a flow channel structure is formed on the surface of the gas diffusion layer, and the unetched portion becomes the ridge of the flow channel, the thickness of the ridge is the same as the thickness of the unetched portion of the gas diffusion layer, and / or the thickness of the ridge is 370 μm or less, the width of the flow channel is 0.1 to 2 mm, and the flow channel formed by the etching has a depth of 10 to 200 μm and a width of 0.1 to 2 mm. The integrated gas diffusion layer for a fuel cell according to claim 2, characterized in that.

4. The method of etching includes laser engraving, and / or the method of pressing includes either machining or mechanical pressing, and / or the flow channel structure includes any one of a serpentine flow field, a comb-shaped flow field, and a parallel flow field. The integrated gas diffusion layer for a fuel cell according to any one of claims 1 to 3, characterized in that.

5. The material of the gas diffusion layer includes carbon paper manufactured by Toray Industries, Inc. The integrated gas diffusion layer for a fuel cell according to claim 4, characterized in that.

6. Using software to design different types of flow channel structures, introducing the designed flow channel structure into a laser marking machine or a machining device, pressing carbon paper with the laser engraving or machining device to obtain an integrated gas diffusion layer having the flow channel structure, or manufacturing a mold having the flow channel structure using a 3D printing method, placing carbon paper on the mold and pressing it to obtain the integrated gas diffusion layer of the flow channel structure, and / or, the integrated gas diffusion layer is manufactured by a laser marking machine, a milling machine or a sheet press machine, and / or, the software includes UG software, and the method for manufacturing an integrated gas diffusion layer for a fuel cell according to any one of claims 1 to 5 is characterized in that.

7. A membrane electrode for a fuel cell provided with the integrated gas diffusion layer according to any one of claims 1 to 5, which is obtained by performing an integrated GDL assembly on the integrated gas diffusion layer and a bipolar plate, and the bipolar plate is a flat metal plate or a graphite plate, a membrane electrode for a fuel cell.

8. A fuel cell provided with the integrated gas diffusion layer according to any one of claims 1 to 5, or the membrane electrode according to claim 7.

9. The peak power density of the battery under the condition of a back pressure of 0 kPa is 1.2 W / cm ２ or more, and when the back pressure rises to 50 kPa, the peak power density of the battery reaches 1.4 W / cm ２ The fuel cell according to claim 8, characterized in that it reaches.

10. Use of the integrated gas diffusion layer according to any one of claims 1 to 5 in an energy conversion device.

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