A bipolar plate for a proton exchange membrane fuel cell

Abstract

The application provides a gas flow channel structure for a proton exchange membrane fuel cell bipolar plate, which mainly comprises an anode plate and a cathode plate, and is formed by parallel arrangement of eight guide blocks and straight guide columns with a square cross section. The circular arc protrusions of the guide blocks near the gas inflow direction are arranged at the inlet of the flow channel, the straight guide columns near the outlet of the flow channel are arranged in transverse parallel arrangement, the main gas flow channel is an interlaced flow channel formed by two main guide blocks, six auxiliary guide blocks and parallel straight guide blocks arranged in sequence, and there are gap flow channels between the interlaced flow channels formed by the guide blocks. The application can effectively enhance the uniformity of the internal reaction gas distribution of the proton exchange membrane fuel cell bipolar plate, improve the utilization rate of the reaction gas, effectively prevent or alleviate the waterlogging situation, and to a certain extent, improve the heat dissipation performance of the proton exchange membrane fuel cell, so that the comprehensive performance of the proton exchange membrane fuel cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane fuel cells, and designs the flow channel structure of the bipolar plate of a proton exchange membrane fuel cell, especially the gas flow channel structure that is beneficial to the output performance of the proton exchange membrane fuel cell. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) use hydrogen and oxygen as fuel, directly converting chemical energy into electrical energy, making them one of the most environmentally friendly energy conversion devices. Hydrogen and oxygen serve as the reactants in the PEMFC. After being introduced into the gas flow channel, the reactants diffuse towards the center of the fuel cell into the gas diffusion layer, and then further diffuse to the catalyst layer to carry out the electrochemical reaction. The gas flow channel, porous gas diffusion layer, and catalyst layer of the PEMFC are essential pathways for the transport of fuel reactants, affecting the entire mass transfer process of the fuel cell and ultimately influencing its fuel utilization efficiency and overall output performance.

[0003] Parallel flow channels are a typical type of flow channel in traditional fuel cells. A typical parallel flow channel includes an inlet flow channel with an inlet, an outlet flow channel with an outlet, and at least one branch flow channel. The inlet of each branch flow channel is connected to the inlet flow channel, and the outlet of each branch flow channel is connected to the outlet flow channel. The reactant gas enters the flow channel through the inlet flow channel, passes through each branch flow channel, and exits through the outlet flow channel. Due to the structural characteristics of parallel flow channels, the utilization rate of the reactant gas is relatively low. Furthermore, under conditions of high humidity reactant gas and high current density, the moisture generated in the cell is difficult to remove effectively and promptly, easily accumulating in the cathode flow channel, blocking mass transfer, and causing a "flooding" phenomenon, thus affecting fuel cell performance.

[0004] The gas flow channel design of proton exchange membrane fuel cells commonly uses traditional parallel flow channels, serpentine flow channels, or interdigitated flow channels. These flow channels have in common that their width is basically the same as that of the branch flow channels. Flow channels with this structure usually have large pressure loss and poor flow capacity. Summary of the Invention

[0005] Therefore, it is necessary to propose a gas flow channel structure for the bipolar plate of a proton exchange membrane fuel cell to address the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a gas flow channel structure for a bipolar plate of a proton exchange membrane fuel cell, comprising a fuel cell, wherein the fuel cell is assembled from multiple single cells stacked together, each single cell comprising an anode plate, a cathode plate, and a membrane electrode assembly. The anode plate and cathode plate are sized to match and can be combined to form a bipolar plate. A square groove-shaped flow field is provided in the middle of both the anode plate and the cathode plate. A flow channel inlet penetrating one side of the square groove-shaped flow field is provided on both the anode plate and the cathode plate, and two symmetrically distributed flow channel outlets penetrating the square groove-shaped flow field are provided on the other side. A gas flow channel structure is provided within the square groove-shaped flow field. The gas flow channel structure consists of eight guide blocks and straight guide columns with a square cross-section arranged in parallel. The eight guide blocks are arranged near the gas flow channel inlet, and the arcs of the guide blocks in the same row point in the same direction. The convex part of the arc is close to the gas inflow direction. The straight guide columns are arranged in parallel near the gas flow channel outlet. The guide columns in the square groove flow field are arranged in sequence to form a semi-interlaced and semi-parallel flow channel. The guide blocks are not connected to each other, and multiple gap channels are formed between adjacent interlaced flow channels. The anode plate and the cathode plate are provided with a side groove around the edge of the square groove flow field. The membrane electrode is matched with the size of the side groove and installed in the side groove. The membrane electrode is composed of an anode gas diffusion layer, an anode gas catalyst layer, a proton exchange membrane, a cathode gas catalyst layer, and a cathode gas diffusion layer arranged in sequence. The anode plate and the cathode plate are provided with four fixing holes at their four corners.

[0007] The length L1 of the main flow block satisfies 5mm≤L1≤6mm; the length L2 of the secondary flow block satisfies 3mm≤L2≤4mm; the distance D1 between the main flow blocks in the same group satisfies 0.4mm≤D1≤0.6mm; the distance D2 between the secondary flow blocks in the same group satisfies 0.2mm≤D2≤0.3mm; the distance D3 between the flow block and the straight flow column satisfies 2mm≤D3≤3mm; and the distance D4 between the straight flow columns satisfies 1mm≤D4≤2mm.

[0008] The bipolar plate and the flow guide column and flow guide block are made of template, metal plate or composite plate, and the surface of the flow guide column and flow guide block is coated with a hydrophobic material coating.

[0009] Compared with the prior art, the beneficial effects of the present invention are:

[0010] 1. The proton exchange membrane fuel cell bipolar plate gas flow channel structure of the present invention adopts a flow channel with a guide block, which ensures that the guide block and the guide column are not connected to each other, greatly increasing the direct contact area between the reactant gas and the reaction layer, effectively improving the diffusion of the reactant gas to the gas diffusion layer, and improving the output performance of the proton exchange membrane fuel cell.

[0011] 2. The flow channel evenly distributes the reactant gas introduced from the flow channel inlet at the inlet. This design allows the reactant gas to flow more evenly into all parts of the proton exchange membrane fuel cell from the flow channel inlet.

[0012] 3. The hydrophobic coating on the surface of the guide blocks and guide columns further enhances the drainage capacity of the flow channel. Attached Figure Description

[0013] Figure 1 This is an exploded view of the single-cell structure of the present invention;

[0014] Figure 2 This is a three-dimensional view of the bipolar plate of the present invention;

[0015] Figure 3 This is a plan view of the bipolar plate of the present invention;

[0016] Figure 4 This is a schematic diagram of a partial flow channel structure of the present invention.

[0017] In the diagram: 1. Anode plate; 2. Cathode plate; 3. Membrane electrode; 4. Flow channel inlet; 5. Flow channel outlet; 6. Gap flow channel; 7. Side groove; 8. Fixing hole; 9. Guide block; 10. Straight guide column; 11. Semi-staggered semi-parallel flow channel. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] Example 1: As Figures 1-4As shown, the present invention provides a technical solution: a gas flow channel structure for a bipolar plate of a proton exchange membrane fuel cell. The fuel cell is composed of multiple single cells stacked together. Each single cell includes an anode plate 1, a cathode plate 2, and a membrane electrode 3. The anode plate 1 and cathode plate 2 are sized to match and form a bipolar plate. A square groove-shaped flow field is provided in the middle of the anode plate 1 and cathode plate 2. A flow channel inlet 4 penetrating one side of the square groove-shaped flow field is provided on both the anode plate 1 and cathode plate 2, and two symmetrically distributed flow channel outlets 5 penetrating the square groove-shaped flow field are provided on the other side. A gas flow channel structure is provided within the square groove-shaped flow field. The gas flow channel structure is composed of eight guide blocks 9 and straight guide columns 10 with a cross-section of a regular square arranged in parallel. The eight guide blocks 9 are arranged near the gas... At the inlet of the flow channel, the arcs of the guide blocks 9 in the same row point in the same direction, and the convex part of the arc is close to the gas inflow direction. The straight guide columns 10 are arranged in parallel in the square groove flow field near the gas flow channel outlet to form a semi-interlaced and semi-parallel flow channel. The guide blocks 9 are not connected to each other and multiple gap channels 6 are formed between adjacent interlaced flow channels. The anode plate 1 and the cathode plate 2 are provided with a side groove 7 around the edge of the square groove flow field. The membrane electrode 3 is matched with the side groove 7 in size and installed in the side groove 7. The membrane electrode 3 is composed of an anode gas diffusion layer, an anode gas catalyst layer, a proton exchange membrane, a cathode gas catalyst layer and a cathode gas diffusion layer in sequence. The anode plate 1 and the cathode plate 2 are provided with four fixing holes 8 at their four corners.

[0021] In this embodiment, when the fuel cell starts working, the reactant gas enters the flow channel from the inlet 4. Guided by the guide block 9 at the inlet 4, the reactant gas flows more evenly into the semi-interlaced, semi-parallel flow channel 11. After the reaction, it converges through the latter half of the parallel flow channel and exits at the outlet 5. The straight guide column 10 and the guide block 9 are not connected to each other. This flow channel significantly increases the contact area between the reactant gas and the reaction layer, allowing the reaction to diffuse more efficiently and evenly into the gas diffusion layer and gas catalyst layer, improving the utilization rate of the reactant gas. Simultaneously, the water generated in the cathode-side catalyst layer can also diffuse more effectively and rapidly into the flow channel and be discharged.

[0022] like Figure 4 As shown, the length L1 of the main flow block satisfies 5mm≤L1≤6mm; the length L2 of the secondary flow block satisfies 3mm≤L2≤4mm; the distance D1 between the main flow blocks in the same group satisfies 0.4mm≤D1≤0.6mm; the distance D2 between the secondary flow blocks in the same group satisfies 0.2mm≤D2≤0.3mm; the distance D3 between the flow block and the straight flow column satisfies 2mm≤D3≤3mm; and the distance D4 between the straight flow columns satisfies 1mm≤D4≤2mm.

[0023] In this implementation plan, different materials can be selected according to actual needs, such as Figure 1As shown, the materials of the anode plate 1, cathode plate 2, flow guide block 9 and straight flow guide column 10 are generally graphite plate, metal plate or composite plate.

[0024] like Figures 1-4 As shown, the surfaces of the flow guide block 9 and the straight flow guide column 10 are coated with a hydrophobic coating. In this embodiment, the hydrophobic coating on the flow guide block 9 and the straight flow guide column 10 further enhances the drainage capacity of the flow channel.

[0025] This invention combines the features of parallel flow channels, gap flow channels, corrugated flow channels, and variable diameter flow channels, while increasing the direct contact area between the reactant gas and the reaction layer. It enhances the utilization rate of the reactant gas in the flow channel, the uniformity of gas diffusion, and the drainage capacity of the flow channel, effectively preventing or mitigating flooding, improving water management of fuel cells, and enhancing the output performance and stability of proton exchange membrane fuel cells.

[0026] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A bipolar plate for a proton exchange membrane fuel cell, characterized in that, include: A fuel cell is assembled from multiple stacked single cells, each single cell including an anode plate, a cathode plate, and a membrane electrode assembly (MEA). The anode and cathode plates are sized to match and can be combined to form a bipolar plate. A square groove-shaped flow field is provided in the middle of both the anode and cathode plates. A flow channel inlet is provided on one side of the square groove-shaped flow field on both the anode and cathode plates, and two symmetrically distributed flow channel outlets are provided on the other side. A gas flow channel structure is provided within the square groove-shaped flow field. The gas flow channel structure consists of eight guide blocks and straight guide columns with a square cross-section arranged in parallel. The eight guide blocks include two main guide blocks and six secondary guide blocks. The arcs of the guide blocks in the same row point in the same direction, and the convex part of the arc is close to the gas inflow direction. The straight guide columns are arranged in parallel near the gas flow channel outlet. The guide columns in the square groove-shaped flow field are arranged sequentially to form a semi-staggered and semi-parallel flow channel. The guide blocks are not connected to each other, and multiple gap channels are formed between adjacent staggered flow channels. The outlet of the flow channel inlet is directly opposite the gap flow channel of the main flow block. After the reaction gas is split, it flows through the gap flow channel of the secondary flow block. Neither the main nor the secondary flow block is connected to the side walls of the bipolar plate. The reactant gas enters the flow channel from the inlet and is guided by the guide block at the inlet, allowing the reactant gas to flow more evenly into the semi-interlaced and semi-parallel flow channel. After the reaction, the gas converges through the parallel flow channel in the latter half and is discharged at the outlet. The length L1 of the main flow block satisfies 5mm≤L1≤6mm; the length L2 of the secondary flow block satisfies 3mm≤L2≤4mm; the distance D1 between the main flow blocks in the same group satisfies 0.4mm≤D1≤0.6mm. The distance D2 between the secondary guide blocks in the same group satisfies: 0.2mm≤D2≤0.3mm; the distance D3 between the secondary guide block and the straight guide column satisfies: 2mm≤D3≤3mm; the distance D4 between the straight guide columns satisfies: 1mm≤D4≤2mm.

2. The bipolar plate according to claim 1, characterized in that, The anode plate and the cathode plate are provided with a side groove around the edge of the square groove-shaped flow field, and the membrane electrode is matched with the size of the side groove and installed in the side groove.

3. The bipolar plate according to claim 1, characterized in that, The membrane electrode is composed of an anode gas diffusion layer, an anode gas catalyst layer, a proton exchange membrane, a cathode gas catalyst layer, and a cathode gas diffusion layer in sequence. The anode plate and the cathode plate are provided with four fixing holes at their four corners.

4. The bipolar plate according to claim 1, characterized in that, The bipolar plate and the flow guide column and flow guide block are made of template, metal plate or composite plate, and the surface of the flow guide column and flow guide block is coated with a hydrophobic material coating.

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