CN115663211B - Gas diffusion layer and fuel cell - Google Patents

Abstract

The present application relates to the technical field of fuel cells, and in particular to a gas diffusion layer and a fuel cell. The gas diffusion layer includes a metal felt layer and a metal mesh layer. When used in a unit cell of a fuel cell, the metal felt layer and the metal mesh layer are stacked in sequence between the CCM and the plate of the unit cell. The metal felt layer is located close to the CCM. One side is attached to the CCM, and the metal mesh layer is located between the electrode plates. One side of the metal mesh layer is attached to the metal felt layer, and the other side is attached to the electrode plate, so that the metal felt layer, An electrical connection is formed between the metal mesh layer and the electrode plate. By using a gas diffusion layer in the form of metal felt and metal mesh, the gas diffusion layer can have stronger mechanical stability and will not undergo large compression deformation due to the pressure experienced by the unit cells during assembly, thus making the unit cell assembly easier. It has smaller dimensional changes, which makes it easier to assemble the unit cells and improves the assembly efficiency.

Description

Gas diffusion layer and fuel cell

Technical field

The present application relates to the technical field of fuel cells, and in particular to a gas diffusion layer and a fuel cell.

Background technique

The unit cell of a PEM (Polymer Electrolyte Membrane, polymer electrolyte membrane) hydrogen fuel cell usually includes a catalyst coated membrane (CCM, Catalyst coated membrane) and anode plates and cathode plates disposed on both sides of the CCM, and the CCM and the anode plate and A gas diffusion layer (GDL, Gas Diffusion Layer) is stacked between the CCM and the cathode plate.

Existing unit cells usually use carbon paper stacked between the electrode plate and the CCM to form a GDL. However, the GDL formed by stacking carbon paper has poor mechanical stability and is easily compressed and deformed when under pressure, which also causes the unit to When the battery is being assembled, it is easy to undergo dimensional changes due to pressure, which in turn affects the assembly of the unit cells, resulting in low assembly efficiency.

Contents of the invention

The object of the present invention is to provide a gas diffusion layer and a fuel cell, so as to improve the mechanical stability of the gas diffusion layer to a certain extent and make it less susceptible to pressure deformation.

The invention provides a gas diffusion layer, which includes a metal felt layer and a metal mesh layer;

The metal felt layer and the metal mesh layer are used to be stacked in sequence between the catalyst coating membrane and the electrode plate of the fuel cell, and the metal mesh layer is located on the side close to the electrode plate;

The metal felt layer and the metal mesh layer are electrically connected, and the metal mesh layer is used to electrically connect with the electrode plate.

Further, the metal mesh layer includes a small hole metal mesh and a large hole metal mesh that are stacked in sequence, and the small hole metal mesh is located on a side close to the metal felt layer.

Furthermore, the small-hole metal mesh and the large-hole metal mesh are both formed with rhombus-shaped meshes, and there is a predetermined angle of dislocation between the rhombus-shaped meshes of the small-hole metal mesh and the large-hole metal mesh.

Further, the small-hole metal mesh is provided with at least one layer. When the small-hole metal mesh is multi-layered, there is a predetermined angle of misalignment between the diamond-shaped mesh holes of the small-hole metal mesh in two adjacent layers;

And/or, the large-hole metal mesh is provided with at least one layer. When the large-hole metal mesh is multi-layered, there is a predetermined angle of misalignment between the rhombus meshes of the large-hole metal mesh in two adjacent layers. .

Further, the two diagonals of the rhombus mesh of the small-hole metal mesh are k1 and k2 respectively, where the size of k1 is 0.1mm-0.5mm, and the size of k2 is 0.3mm-0.8mm;

The two diagonals of the rhombus mesh of the large-hole metal mesh are s1 and s2 respectively, where the size of s1 is 2mm-4mm, and the size of s2 is 1mm-1.5mm.

Further, the metal felt layer, the metal mesh layer and the electrode plate are pressed and connected through a laminator to achieve electrical connection;

Alternatively, two adjacent ones of the metal felt layer, the metal mesh layer and the pole plate are riveted, welded or bonded through conductive glue to achieve electrical connection.

Further, the material of the metal felt of the metal felt layer is stainless steel or titanium alloy; and/or the material of the metal mesh of the metal mesh layer is stainless steel or titanium alloy;

The surface of the metal felt of the metal felt layer and/or the metal mesh of the metal mesh layer is sprayed with a plating layer having corrosion resistance and conductivity.

Further, the gas diffusion layer further includes a carbon powder microporous layer, and the carbon powder microporous layer is attached to the metal felt layer for one side facing the catalyst coating membrane.

The invention also provides a fuel cell, including an anode gas diffusion layer and a cathode gas diffusion layer;

The anode gas diffusion layer and/or the cathode gas diffusion layer is the gas diffusion layer described in any one of the above.

Furthermore, electrode plates are provided on both sides of the fuel cell, and the electrode plate on one side of the fuel cell provided with the gas diffusion layer described in any one of the above is in the shape of a flat plate.

Compared with the prior art, the beneficial effects of the present invention are:

The gas diffusion layer provided by the invention includes a metal felt layer and a metal mesh layer. The metal felt layer is a layered structure formed of metal felt and has a predetermined thickness. The metal mesh layer is formed of a metal mesh and has a predetermined layered structure; When used in a unit cell for a fuel cell, a metal felt layer and a metal mesh layer are stacked in sequence between the CCM and the plate of the unit cell. The metal felt layer is located on the side close to the CCM and adheres to the CCM. The metal mesh layer It is located close to the electrode plates, and one side of the metal mesh layer is attached to the metal felt layer, and the other side of the metal mesh layer is attached to the electrode plates, so that there is a formation between the metal felt layer, the metal mesh layer and the electrode plates. Electrical connection.

Compared with the traditional gas diffusion layer in the form of carbon paper, by using a gas diffusion layer in the form of metal felt and metal mesh, the gas diffusion layer can have stronger mechanical stability and will not be affected by the pressure of the unit cell during assembly. The larger compression deformation occurs, so that the unit cells have smaller dimensional changes during assembly, which makes it easier to assemble the unit cells and improves the assembly efficiency.

The present invention also provides a fuel cell, including the gas diffusion layer, so the fuel cell also has the beneficial effects of the gas diffusion layer.

Description of the drawings

In order to more clearly explain the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description The drawings illustrate some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a schematic structural diagram of a gas diffusion layer used on the cathode side of a fuel cell according to an embodiment of the present invention;

Figure 2 is a schematic structural diagram of a gas diffusion layer used on the anode side of a fuel cell according to an embodiment of the present invention;

Figure 3 is a schematic structural diagram of the gas diffusion layer provided by the embodiment of the present invention being used on the anode side and cathode side of the fuel cell;

Figure 4 is a schematic structural diagram of the metal felt layer of the gas diffusion layer provided by an embodiment of the present invention;

Figure 5 is a schematic structural diagram of the small hole metal mesh of the gas diffusion layer provided by the embodiment of the present invention;

Figure 6 is an enlarged view of point A in Figure 5;

Figure 7 is a schematic structural diagram of a large-porous metal mesh of a gas diffusion layer provided by an embodiment of the present invention;

Figure 8 is an enlarged view of B in Figure 7.

Reference signs:

1-CCM, 2-carbon powder microporous layer, 3-metal felt layer, 4-small hole metal mesh, 5-large hole metal mesh, 6-pole plate.

Detailed ways

The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, not all, of the embodiments of the present invention.

The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the appended drawings is not intended to limit the scope of the claimed invention, but rather to represent selected embodiments of the invention.

Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limitations of the invention. Furthermore, the terms “first”, “second” and “third” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

The gas diffusion layer and fuel cell according to some embodiments of the present application are described below with reference to FIGS. 1 to 8 .

A first aspect of the present application provides a gas diffusion layer (GDL) for use in a unit cell of a fuel cell; in the unit cell, the gas diffusion layer is used to stack a catalyst coating membrane (CCM) and an electrode of the unit cell. Between the plates, the plate can be an anode plate or a cathode plate. The gas diffusion layer stacked between the anode side of the CCM and the anode plate is the anode GDL. The gas diffusion layer stacked between the cathode side of the CCM and the cathode plate The layer is the cathode GDL.

As shown in Figure 1, the gas diffusion layer of the present application includes a metal felt layer 3 and a metal mesh layer. The metal felt layer 3 is a layered structure formed by metal felt and has a predetermined thickness. The metal mesh layer is formed by a metal mesh and has a predetermined thickness. Predetermined layered structure; when used in a unit cell of a fuel cell, the metal felt layer 3 and the metal mesh layer are stacked in sequence between the CCM1 and the plate 6 of the unit cell, and the metal felt layer 3 is located on the side close to the CCM1 And fit with CCM1, the metal mesh layer is located between the electrode plates 6, and one side of the metal mesh layer is fit with the metal felt layer 3, and the other side of the metal mesh layer is fit with the electrode plate 6, so that Electrical connections are formed between the metal felt layer 3, the metal mesh layer and the pole plate 6.

Compared with the traditional gas diffusion layer in the form of carbon paper, by using a gas diffusion layer in the form of metal felt and metal mesh, the gas diffusion layer can have stronger mechanical stability and will not be affected by the pressure of the unit cell during assembly. The larger compression deformation occurs, so that the unit cells have smaller dimensional changes during assembly, which makes it easier to assemble the unit cells and improves the assembly efficiency.

In one embodiment of the present application, preferably, as shown in Figure 1 and Figures 5 to 8, the metal mesh layer includes a small-hole metal mesh 4 with smaller meshes and a large-hole metal mesh with larger meshes. 5. The small hole metal mesh 4 and the large hole metal mesh 5 are stacked in sequence, and the small hole metal mesh 4 is located on the side close to the metal felt.

The metal felt is formed with smaller holes for gas circulation than the mesh of the small hole metal mesh 4. Therefore, by sequentially stacking the metal felt, the small hole metal mesh 4 and the large hole metal mesh 5, the gas diffusion layer is formed along the metal felt. The superimposition direction forms a porosity gradient and a pore size gradient, thereby ensuring effective diffusion of reaction gases in the unit cell.

In this embodiment, preferably, as shown in Figure 4, the porosity of the metal felt is between 30% and 70%; further preferably, as shown in Figures 5 to 8, the small hole metal mesh 4 and the large hole The metal mesh 5 is formed with a diamond-shaped mesh. The diamond-shaped mesh of the small-hole metal mesh 4 has two diagonals, namely k1 and k2, where the size of k1 is 0.1mm-0.5mm; the diamond-shaped mesh of the large-hole metal mesh 5 The mesh also has two diagonals, namely s1 and s2, where the size of s1d is 2mm-4mm and the size of s2 is 1mm-1.5mm.

In this embodiment, preferably, for the small hole metal mesh 4 and the large hole metal mesh 5 that are stacked together, when superimposing, the rhombus mesh between the small hole metal mesh 4 and the large hole metal mesh 5 is at a predetermined angle. The misalignment of the angle means that when the small hole metal mesh 4 and the large hole metal mesh 5 are arranged, the diagonals of the rhombus meshes of the two are at a predetermined angle.

Preferably, the angle between the diagonals of the rhombus-shaped mesh of the small-hole metal mesh 4 and the large-hole metal mesh 5 is 0-90 degrees.

By staggering the small-hole metal mesh 4 and the large-hole metal mesh 5, the mechanical stability of the molecular diffusion layer can be improved to a certain extent, making the molecular diffusion layer less likely to deform, and at the same time, the reaction gas flow can be adjusted to a certain extent. The flow resistance when passing through the gas diffusion layer; and the misalignment angle between the rhombus mesh holes of the small hole metal mesh 4 and the large hole metal mesh 5 can be adjusted according to the required gas flow resistance.

In this embodiment, preferably, the small hole metal mesh 4 can be provided with one or more layers, and when the small hole metal mesh 4 is provided with multiple layers, the diamond-shaped mesh holes of the adjacent two layers of small hole metal mesh 4 are also in the shape of Dislocation arrangement at a predetermined angle.

Preferably, the large-hole metal mesh 5 can also be provided with one or more layers, and when the large-hole metal mesh 5 is provided with multiple layers, the diamond-shaped mesh holes of the adjacent two layers of large-hole metal mesh 5 are also arranged at a predetermined angle. .

In one embodiment of the present application, preferably, the metal felt of the metal felt layer 3, the metal mesh of the metal mesh layer, and the electrode plate 6 can be made of stainless steel or titanium alloy, such as 316L stainless steel, titanium alloy TA1 or TA2, etc.

Further preferably, the surfaces of the metal felt of the metal felt layer 3 and the metal mesh of the metal mesh layer can be spray-coated with corrosion-resistant and conductive coatings.

In one embodiment of the present application, preferably, when the metal felt layer 3, the metal mesh layer and the electrode plate 6 are assembled and connected, a laminator can be directly used for pressure connection, so that the three are connected together and form Electrical connection; at the same time, there is a slight fit between the metal felt layer 3 and the metal mesh layer, as well as between the metal meshes of the metal mesh layer, thereby improving the conductivity of the plate tool assembly formed after the connection.

Preferably, the metal felt layer 3, the metal mesh layer and the electrode plate 6 can also be connected by riveting, bonding with conductive glue or welding, so that the three are connected together and form an electrical connection; and after the connection is completed, they can also be connected. Use a laminator to apply a certain amount of pressure to the connected tooling and press it flat, so that there is a slight fit between the metal felt layer 3 and the metal mesh layer, as well as between the metal mesh layers of the metal mesh layer, to improve the quality of the connection. Conductivity of plate tooling components.

Further preferably, the metal felt layer 3, the metal mesh layer and the electrode plate 6 are connected by welding. There are many ways of welding connection, such as diffusion welding, resistance spot welding, laser welding, etc.; by welding, It is equivalent to forming the two layers that need to be welded into one, which means that there is no contact surface between the two layers; thus, through welding connection, it is equivalent to reducing the number of contact surface layers of the plate tooling assembly, thereby making the electrode The internal resistance of the plate tooling assembly is lower.

In one embodiment of the present application, preferably, the gas diffusion layer also includes a carbon powder microporous layer 2, and the carbon powder microporous layer 2 is attached to the side of the metal felt layer 3 facing CCM1, so that between CCM1 and the gas diffusion layer Add support between them to protect CCM1 from damage, and also reduce the contact resistance between metal felt layer 3 and CCM1 to a certain extent.

A second aspect of the present application provides a fuel cell including an anode gas diffusion layer and a cathode gas diffusion layer, where at least one of the anode gas diffusion layer and the cathode gas diffusion layer is the gas diffusion layer of any of the above embodiments.

In this embodiment, the fuel cell includes a gas diffusion layer, so the fuel cell has all the beneficial effects of the gas diffusion layer, which will not be described again one by one.

In a fuel cell, specifically a unit cell of a fuel cell, it can be as shown in Figure 1. The cathode gas diffusion layer of the fuel cell adopts the gas diffusion layer of any of the above embodiments, and the anode gas diffusion layer adopts a traditional gas diffusion layer. diffusion layer.

Alternatively, as shown in FIG. 2 , the anode gas diffusion layer of the fuel cell adopts the gas diffusion layer of any of the above embodiments, and the cathode gas diffusion layer adopts a traditional gas diffusion layer.

Or, as shown in FIG. 3 , both the anode gas diffusion layer and the cathode gas diffusion layer of the fuel cell adopt the gas diffusion layer of any of the above embodiments.

In this embodiment, the fuel cell includes the gas diffusion layer of any of the above embodiments. Therefore, the fuel cell has all the beneficial effects of the gas diffusion layer, which will not be described again here.

In this embodiment, preferably, when the anode GDL or cathode GDL of the unit cell adopts the gas diffusion layer of the present application, since the metal felt of the metal felt layer and the metal mesh of the metal mesh layer are formed compared with the traditional carbon paper, There are enough channels for gas circulation, so the corresponding anode plate or cathode plate can be set in a flat plate shape. When using a traditional gas diffusion layer in the form of carbon paper, the electrode plate requires a channel for gas flow at the bend, making the structure and processing of the electrode plate relatively complex.

In this embodiment, preferably, when the anode GDL or cathode GDL of the unit cell adopts the gas diffusion layer of the present application, since the metal felt of the metal felt layer and the metal mesh of the metal mesh layer are formed compared with the traditional carbon paper. There are enough channels for gas circulation, so the corresponding anode plate or cathode plate can be set in a flat plate shape. When using a traditional gas diffusion layer in the form of carbon paper, the electrode plate requires a channel for gas flow at the bend, making the structure and processing of the electrode plate relatively complex.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention. scope.

Claims (6)

1. A gas diffusion layer, characterized in that it includes a metal felt layer and a metal mesh layer; The metal felt layer and the metal mesh layer are used to be stacked in sequence between the catalyst coating membrane and the electrode plate of the fuel cell, and the metal mesh layer is located on the side close to the electrode plate; The metal felt layer and the metal mesh layer are electrically connected, and the metal mesh layer is used to electrically connect with the electrode plate; The metal mesh layer includes a small hole metal mesh and a large hole metal mesh that are stacked in sequence, and the small hole metal mesh is located on the side close to the metal felt layer; The small-hole metal mesh and the large-hole metal mesh are both formed with rhombus-shaped meshes, and there is a predetermined angle of dislocation between the rhombus-shaped meshes of the small-hole metal mesh and the large-hole metal mesh; The small-hole metal mesh is provided with at least one layer. When the small-hole metal mesh is multi-layered, the diamond-shaped mesh holes of the small-hole metal mesh in two adjacent layers have a predetermined angle of dislocation; And/or, the large-hole metal mesh is provided with at least one layer. When the large-hole metal mesh is multi-layered, there is a predetermined angle of misalignment between the rhombus meshes of the large-hole metal mesh in two adjacent layers. ; The two diagonals of the diamond-shaped mesh of the small-hole metal mesh are k1 and k2 respectively, where the size of k1 is 0.1mm-0.5mm, and the size of k2 is 0.3mm-0.8mm; The two diagonals of the rhombus mesh of the large-hole metal mesh are s1 and s2 respectively, where the size of s1 is 2mm-4mm, and the size of s2 is 1mm-1.5mm. 2. The gas diffusion layer according to claim 1, characterized in that the metal felt layer, the metal mesh layer and the electrode plate are pressed and connected through a laminator to achieve electrical connection; Alternatively, two adjacent ones of the metal felt layer, the metal mesh layer and the pole plate are riveted, welded or bonded through conductive glue to achieve electrical connection. 3. The gas diffusion layer according to claim 1, wherein the material of the metal felt of the metal felt layer is stainless steel or titanium alloy; and/or the material of the metal mesh of the metal mesh layer is stainless steel or titanium alloy. titanium alloy; The surface of the metal felt of the metal felt layer and/or the metal mesh of the metal mesh layer is sprayed with a plating layer having corrosion resistance and conductivity. 4. The gas diffusion layer according to claim 1, further comprising a carbon powder microporous layer attached to the metal felt layer for facing one side of the catalyst coating membrane. side. 5. A fuel cell, characterized in that it includes an anode gas diffusion layer and a cathode gas diffusion layer; The anode gas diffusion layer and/or the cathode gas diffusion layer is the gas diffusion layer according to any one of claims 1 to 4. 6. The fuel cell according to claim 5, characterized in that pole plates are provided on both sides of the fuel cell, and the fuel cell is provided with a gas diffusion device according to any one of claims 1 to 4. The plate on one side of the layer is flat.