阅读说明：本技术 一种气体扩散层及其制备方法 (Gas diffusion layer and preparation method thereof ) 是由 毛学伟 林卫兵 滕彪 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种气体扩散层及其制备方法,包括以下步骤S1、在一金属薄板的一侧表面加工出并排的长条形凹槽；S2、对具有长条凹槽的金属薄板进行切割,切割成需要的形状；S3、将若干块切割好的金属薄板进行叠加,相邻的金属薄板之间紧贴并进行牢固连接,形成内部有规则孔隙结构的金属块；S4、对金属块沿着其横截面进行切割,切割的厚度与需要的气体扩散层的厚度相配,切割下来形成表面规则地布满微孔的薄片结构作为气体扩散层。本发明可以解决现有的钛纤维毡板导流效果较差、接触效率不高、接触面电阻较大的问题。(The invention discloses a gas diffusion layer and a preparation method thereof, comprising the following steps of S1, processing a side-by-side strip-shaped groove on the surface of one side of a metal sheet; s2, cutting the metal sheet with the strip-shaped groove into a required shape; s3, overlapping a plurality of cut metal sheets, and enabling adjacent metal sheets to be tightly attached and firmly connected to form metal blocks with regular pore structures inside; and S4, cutting the metal block along the cross section of the metal block, wherein the cutting thickness is matched with the thickness of the required gas diffusion layer, and cutting to form a sheet structure with the surface regularly distributed with micropores as the gas diffusion layer. The invention can solve the problems of poor flow guiding effect, low contact efficiency and large contact surface resistance of the existing titanium fiber felt plate.)

1. A method of preparing a gas diffusion layer, comprising the steps of:

s1, processing a side-by-side elongated groove on one side surface of a metal sheet;

s2, cutting the metal sheet with the strip-shaped groove formed in the step S1 into a required shape;

s3, overlapping a plurality of metal sheets cut in the step S2, and enabling adjacent metal sheets to be tightly attached and firmly connected to form a metal block with a regular pore structure inside;

and S4, cutting the metal block in the step S3 along the cross section of the metal block, wherein the cutting thickness is matched with the thickness of the required gas diffusion layer, and the cut metal block is cut to form a sheet structure with the surface regularly distributed with micropores as the gas diffusion layer.

2. The method of preparing a gas diffusion layer according to claim 1, wherein:

the step S1 includes the following steps:

s11, manufacturing of a printing roller: carving parallel grooves on the printing roller with a smooth surface;

s12, rolling the metal sheet using the roll prepared in step S11, and forming linear grooves in parallel on one surface of the metal sheet.

3. The method of preparing a gas diffusion layer according to claim 2, characterized in that: the grooves on the plate roller are arranged side by side along the axial direction or the circumferential direction of the plate roller.

4. The method of preparing a gas diffusion layer according to claim 1, wherein: in step S1, the elongated grooves on the surface of the metal sheet are formed by laser processing, etching processing, ultrasonic wave engraving processing, or electrical discharge processing.

5. The method of preparing a gas diffusion layer according to claim 1, wherein: the metal sheet is made of titanium metal or titanium alloy.

6. The method of preparing a gas diffusion layer according to claim 1, wherein: and performing surface coating treatment on the gas diffusion layer after the step S4, wherein the surface coating treatment is passivation anticorrosion treatment and hydrophilic treatment.

7. A gas diffusion layer produced by the production method according to any one of claims 1 to 6.

Technical Field

The invention relates to the field of hydrogen production by water electrolysis, in particular to a gas diffusion layer and a preparation method thereof.

Background

Electrolytic hydrogen production is considered as a novel energy storage mode, and is one of the methods capable of consuming renewable energy sources on a large scale, and is well accepted in the world. The mode of electrolytic hydrogen production mainly comprises the traditional alkaline water electrolysis hydrogen production and the emerging solid electrolyte (SPE) water electrolysis hydrogen production, and the SPE water electrolysis hydrogen production has the advantages of high efficiency, small device, quick start and stop, no pollution, high hydrogen production purity and the like, so the device has competitiveness in a new energy power generation scene with great fluctuation elimination.

The SPE electrolytic bath mainly comprises bipolar plates, gas diffusion layers (cathode and anode) and a membrane electrode. The gas diffusion layer mainly has the functions of supporting a membrane electrode, conducting, guiding gas and liquid and the like, and because of strong oxidizing property generated by anode oxygen evolution reaction in the water electrolysis reaction process, the gas diffusion layer and the bipolar plate of the SPE electrolytic cell are mostly made of titanium metal materials. The existing gas diffusion layer for the SPE electrolytic cell mainly adopts a titanium fiber felt plate, and the titanium fiber felt plate has the following problems as the gas diffusion layer:

1. the titanium fiber felt board is formed by lapping and sintering titanium fibers, has disordered internal gaps and has poor flow guide effect on fluid;

2. the microstructure of the surface of the titanium fiber felt plate also presents a disordered state, and on an interface contacted with the membrane electrode, the contact efficiency is low, the contact surface resistance is large, and the efficiency of electrolytic water reaction is influenced.

In order to solve the above problems, a new gas diffusion layer having a flat surface and regular pores is required to satisfy the requirements of contact ratio and flow guiding efficiency.

Disclosure of Invention

The invention provides a gas diffusion layer and a preparation method thereof, which can solve the problems of poor flow guiding effect, low contact efficiency and large contact surface resistance of the existing titanium fiber felt plate.

In order to achieve the above object, in a first aspect, in an embodiment of the present application, the following technical solutions are provided: a method of preparing a gas diffusion layer comprising the steps of:

s1, processing a parallel long-strip-shaped groove on one side surface of the metal sheet;

s2, cutting the metal sheet with the strip-shaped groove formed in the step S1 into a required shape;

s3, overlapping a plurality of metal sheets cut in the step S2, and enabling adjacent metal sheets to be tightly attached and firmly connected to form a metal block with a regular pore structure inside;

and S4, cutting the metal block in the step S3 along the cross section of the metal block, wherein the cutting thickness is matched with the thickness of the required gas diffusion layer, and the cut metal block is cut to form a sheet structure with the surface regularly distributed with micropores as the gas diffusion layer.

Preferably, step S1 includes the following steps:

s11, manufacturing of a printing roller: carving parallel grooves on the printing roller with a smooth surface;

s12, rolling the metal sheet using the roll prepared in step S11, and forming linear grooves in parallel on one surface of the metal sheet.

Preferably, the grooves on the plate roll are arranged side by side along the axial direction or the circumferential direction of the plate roll.

Preferably, the elongated grooves on the surface of the metal sheet in step S1 are formed by laser processing or etching processing or ultrasonic wave engraving processing or electric discharge processing.

Preferably, the metal sheet is made of titanium metal or titanium alloy.

Preferably, the method further comprises performing surface coating treatment on the gas diffusion layer after step S4, wherein the surface coating treatment is passivation anticorrosion treatment and hydrophilic treatment.

In a second aspect, in an embodiment of the present application, there is also provided a gas diffusion layer prepared by the preparation method described in the first aspect.

Compared with the prior art, the invention has the beneficial effects that:

the brand new preparation method is adopted, the preparation method is high in efficiency, the gas diffusion layer with a flat surface and regularly arranged flow guide through holes can be prepared, the gas diffusion layer can be more fully contacted with the membrane electrode, the contact surface resistance is reduced, and the electrolysis efficiency is improved; the flow guide efficiency of gas and liquid can be improved to the maximum extent; therefore, the application is an important innovation of the irregular internal pore structure of the gas diffusion layer for the conventional SPE electrolytic cell, the flow guiding effect of the gas diffusion layer on fluid can be greatly improved, and meanwhile, the contact efficiency of the gas diffusion layer and a membrane electrode can also be improved.

Drawings

FIG. 1 is a flow chart of a production process of the present invention;

fig. 2 is a schematic diagram illustrating the superposition of the metal sheets in step S3 in the manufacturing method of the present invention;

fig. 3 is a schematic view of the metal block formed in step S3 in the production method of the present invention;

FIG. 4 is a schematic structural view of one embodiment of a gas diffusion layer of the present invention;

fig. 5 is a schematic structural view of another embodiment of a gas diffusion layer according to the present invention.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides the following technical scheme for achieving the purpose and solving the problems of poor flow guiding effect, low contact efficiency and large contact surface resistance of the conventional titanium fiber felt plate:

example 1:

as shown in fig. 1, there is provided a method of preparing a gas diffusion layer, including the steps of:

step S1, processing out the elongated groove side by side on one side surface of the metal sheet, the elongated groove is used for forming the micropore on the gas diffusion layer, the gas diffusion layer has an important index, namely the porosity, the area of the micropore accounts for the ratio of the area of the gas diffusion layer, the size of the elongated groove and the thickness of the metal sheet can influence the porosity of the gas diffusion layer, the depth of the elongated groove is set to be a, the width of the elongated groove is b, the distance between the adjacent elongated grooves is c, the total thickness of the metal sheet is d, and by setting the proportion of the four parameters, the gas diffusion layer with certain porosity can be obtained, for example, a: b: c: d is 1: 1: 1: 2, the final porosity of the gas diffusion layer is 25%; four parameters may also be set to a: b: c: d is 1: 2: 2: 4, the final porosity of the gas diffusion layer is 12.5%; again, four parameters are set to a: b: c: d is 1: 1: 2: 2, the final porosity of the gas diffusion layer was 12.5%.

In this embodiment, the cross-sectional shape of the elongated grooves has various options, and may be preferably designed to be rectangular or square, or may be designed to be semicircular, triangular or trapezoidal, and the like, and those skilled in the art may select different shapes of the elongated grooves according to the specific use requirements of the gas diffusion layer.

In this embodiment, in the molding manner of the elongated groove, the application provides a molding manner with higher efficiency, specifically, side-by-side grooves are firstly engraved on a printing roller with a smooth surface; and then rolling the metal sheet by using the manufactured plate roller, processing parallel strip-shaped grooves on the surface of one side of the metal sheet, wherein the grooves on the plate roller are beams for forming the strip-shaped grooves, and rolling the metal sheet by mounting the plate roller with the surface patterns on a roller press, so that the forming of a large number of strip-shaped grooves can be completed at one time.

The grooves on the plate roller are arranged side by side along the axial direction or the circumferential direction of the plate roller, and the elongated grooves can be formed through rolling.

In the practical application process, there are many ways for forming the elongated grooves on the metal sheet, such as laser processing, etching processing, ultrasonic wave engraving processing, or electrical discharge machining, and those skilled in the art can select the elongated grooves according to the needs.

In this embodiment, the metal sheet is preferably made of titanium metal or titanium alloy, and those skilled in the art may also adopt other metal materials or alloy materials with better corrosion resistance.

Step S2, cutting the metal sheet with the strip-shaped groove formed in step S1 into a desired shape, such as a rectangle of 200mm × 500mm, and various cutting methods, such as punching with a trimming machine or wire cutting.

Step S3, as shown in fig. 2-3, stacking a plurality of metal sheets cut in step S2, where the number of stacked metal sheets can be adjusted according to the requirements of the gas diffusion layer, and adjacent metal sheets are tightly attached and firmly connected, specifically, a beam formed by a long strip-shaped groove on a metal sheet located at a lower layer is tightly attached to a smooth back surface of a metal sheet located at an upper layer, and a high-temperature welding process can be adopted, so that the metal sheets can be firmly connected together to form a metal block with a regular pore structure inside, such as a metal block with a size of 200mm × 500mm × 500 mm. Of course, other means of joining the sheets may be used in practice, such as ultrasonic welding, resistance welding, laser welding, etc.

Step S4, cutting the metal block in step S3 along the cross section thereof, the cut thickness matching the thickness of the required gas diffusion layer, such as 0.5mm, cutting to form a sheet structure with pores regularly distributed on the surface as the gas diffusion layer, and cutting the metal block with 200mm × 500mm × 500mm to obtain hundreds of gas diffusion layers with the specification of 500mm × 500mm × 0.5mm, wherein the density of the pores of the formed gas diffusion layer can reach millions to billions per square meter, and the flow guiding effect of the fluid is excellent.

After step S4, step S5 may be added, specifically, the gas diffusion layer is subjected to a surface coating treatment, which is mainly a passivation anticorrosion treatment and a hydrophilic treatment.

Example 2:

in an embodiment of the present application, as shown in fig. 4, the gas diffusion layer is prepared by the preparation method described in embodiment 1, and the specific structure includes a sheet body, where a plurality of micropores penetrating through the sheet body are regularly arranged on the sheet body, and the thickness of the sheet body is preferably 200-800 micrometers, as shown in fig. 4, the micropores are arranged in a rectangular array, or as shown in fig. 5, the micropores are arranged in a plurality of rows, and the micropores in adjacent rows are arranged in a staggered manner, so that the micropores are more uniform, and the area utilization rate of the specially-shaped sheet body can be improved.

The preparation method has high efficiency, can prepare the gas diffusion layer with a flat surface and regularly arranged flow guide through holes, can be more fully contacted with the membrane electrode, reduces the contact surface resistance and improves the electrolysis efficiency; the flow guide efficiency of gas and liquid can be improved to the maximum extent; therefore, the application is an important innovation of the irregular internal pore structure of the gas diffusion layer for the conventional SPE electrolytic cell, the flow guiding effect of the gas diffusion layer on fluid can be greatly improved, and meanwhile, the contact efficiency of the gas diffusion layer and a membrane electrode can also be improved.

In addition, it is to be additionally noted that: the gas diffusion layer manufactured by the method can also be used in the fields of physical and chemical reactions such as but not limited to fuel cells and the like which need to fully disperse or collect fluid, and the performance advantages of the gas diffusion layer can be embodied when the gas diffusion layer is applied in the fields.

It should be noted that all directional indicators (such as up, down, left, right, front, and back) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.