Fuel cell

Abstract

The utility model relates to the technical field of cells, in particular to a fuel cell which comprises a fuel cell body, the fuel cell body comprises a plurality of electrode units and a plurality of bipolar plates, and the electrode units and the bipolar plates are stacked at intervals to form the fuel cell body; the electrode unit comprises a catalyst coating proton membrane and a pair of diffusion layers, and the two sides of the catalyst coating proton membrane are attached to the diffusion layers respectively; the catalyst coating proton membrane comprises a proton exchange membrane and catalyst layers coated on two side surfaces of the proton exchange membrane; the diffusion layer is of a two-layer structure, one layer is a graphite layer, the other layer is a carbon fiber layer, the graphite layer is in contact with the catalyst layer, and the carbon fiber layer is in contact with the bipolar plate; the carbon fiber layer is provided with a first flow channel. The fuel cell is simple in structure, scientific and reasonable in design and convenient to use, air resistance is effectively reduced and a more uniform air field is formed by arranging the first flow channel on the diffusion layer, and the problems that an existing fuel cell is not uniform in air channel and poor in drainage capacity are solved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a fuel cell. Background Technology

[0002] A fuel cell is an energy conversion device with the same composition as a conventional battery. It operates on electrochemical principles, specifically the principle of a galvanic cell, isothermally converting the chemical energy stored in fuel and oxidant directly into electrical energy; therefore, the actual process is a redox reaction. However, existing fuel cells suffer from problems such as uneven gas channels, poor drainage capacity, and low bipolar plate strength. Utility Model Content

[0003] The purpose of this invention is to provide a fuel cell to at least solve the aforementioned technical problems.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A fuel cell includes a fuel cell body, which comprises multiple electrode units and multiple bipolar plates, the electrode units and bipolar plates being stacked at intervals to form the fuel cell body; an end plate is disposed on each side of the fuel cell body, and a current collector is attached between the fuel cell body and the end plates; each electrode unit includes a catalyst-coated proton exchange membrane and a pair of diffusion layers, the catalyst-coated proton exchange membrane being attached to a diffusion layer on each side; the catalyst-coated proton exchange membrane includes a proton exchange membrane and a catalyst layer coated on both sides of the proton exchange membrane; the diffusion layer has a two-layer structure, one being a graphite layer and the other being a carbon fiber layer, the graphite layer being in contact with the catalyst layer and the carbon fiber layer being in contact with the bipolar plates; a first flow channel is formed on the carbon fiber layer.

[0006] Furthermore, the first flow channel is either a straight flow channel or a serpentine flow channel; the width of the first flow channel is 0.6 to 2.2 mm, the flow channel inclination angle is 10 to 50°, the ridge width is 0.3 to 1.5 mm, and the ratio of the flow channel width to the ridge width is 1.47 to 2.0.

[0007] Furthermore, both sides of the bipolar plate are smooth surfaces.

[0008] Furthermore, a second flow channel adapted to the first flow channel is opened on each of the two sides of the bipolar plate. The ridge height of the second flow channel gradually decreases with the direction of gas diffusion, with a maximum reduction of 5%.

[0009] Furthermore, the bipolar plate is a composite structure of a metal plate and a graphite plate, with the anode of the bipolar plate being a graphite plate and the cathode being a metal plate; the cathode surface of the bipolar plate is coated with an anti-corrosion coating, which is at least one of a precious metal coating, a graphite coating, a conductive polymer coating, a metal carbide coating, and a metal oxide coating.

[0010] Furthermore, the electrode unit also includes a pair of encapsulation layers, in which the catalyst-coated proton exchange membrane is encapsulated. The encapsulation layers have openings that expose the effective structure on the catalyst-coated proton exchange membrane, and the diffusion layer is attached to the catalyst-coated proton exchange membrane through the openings. The encapsulation layers have a first coolant flow channel hole, a first hydrogen gas hole, and a first air hole at their respective ends.

[0011] Furthermore, the bipolar plate has a second coolant flow channel hole, a second hydrogen gas hole, and a second air gas hole at each end, corresponding to the first coolant flow channel hole, the first hydrogen gas hole, and the first air gas hole, respectively.

[0012] Furthermore, the end plate is provided with a fourth coolant flow channel hole, a fourth hydrogen gas hole, and a fourth air hole, respectively, corresponding to the first coolant flow channel hole, the first hydrogen gas hole, and the first air gas hole.

[0013] Furthermore, the manifold is provided with a third coolant flow channel hole, a third hydrogen gas hole, and a third air gas hole at both ends, corresponding to the first coolant flow channel hole, the first hydrogen gas hole, and the first air gas hole, respectively.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The diffusion layer of this utility model has a two-layer structure, with a graphite layer and a carbon fiber layer. The first flow channel is set on the carbon fiber layer, which helps to effectively reduce air resistance and form a more uniform air field.

[0016] 2. The bipolar plate of this utility model is a composite structure of metal plate and graphite plate, which has good thermal conductivity, can improve heat transfer efficiency by 20% to 30%, stabilizes the stack temperature, and greatly reduces the stack thickness compared with bipolar plates with a single graphite plate.

[0017] 3. This utility model has a simple structure, a scientific and reasonable design, and is easy to use. It can solve the problems of uneven gas channels, poor drainage capacity, and low bipolar plate strength in existing fuel cells. Attached Figure Description

[0018] Figure 1 This is a first structural diagram of the fuel cell of this utility model.

[0019] Figure 2 This is a second structural diagram of the fuel cell of this utility model.

[0020] Figure 3 This is a structural diagram of the electrode unit of this utility model.

[0021] Figure 4 This is a first structural diagram of the bipolar plate of this utility model.

[0022] Figure 5This is a second structural diagram of the bipolar plate of this utility model (only one side of the second flow channel is shown in the figure).

[0023] The names corresponding to the reference numerals in the attached figures are as follows:

[0024] 1-Electrode unit, 2-Current collector, 3-End plate, 4-Catalyst-coated proton exchange membrane, 5-Sealing layer, 6-Diffusion layer, 7-Bipolar plate, 8-Fuel cell body, 21-Third coolant flow channel hole, 22-Third hydrogen port, 23-Third air port, 31-Fourth coolant flow channel hole, 32-Fourth hydrogen port, 33-Fourth air port, 51-First coolant flow channel hole, 52-First hydrogen port, 53-First air port, 54-Opening, 61-Graphite layer, 62-Carbon fiber layer, 63-First flow channel, 71-Second coolant flow channel hole, 72-Second hydrogen port, 73-Second air port, 74-Second flow channel. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0026] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; of course, they can also refer to a mechanical connection or an electrical connection; furthermore, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] like Figures 1-5As shown, the present invention provides a fuel cell including a fuel cell body 8, which includes multiple electrode units 1 and multiple bipolar plates 7. The electrode units 1 and bipolar plates 7 are stacked at intervals to form the fuel cell body 8. An end plate 3 is respectively provided on both sides of the fuel cell body 8, and a current collector 2 is attached between the fuel cell body 8 and the end plate 3. The electrode unit 1 includes a catalyst-coated proton exchange membrane 4 and a pair of diffusion layers 6. The catalyst-coated proton exchange membrane 4 is attached to a diffusion layer 6 on each side.

[0029] The fuel cell body 8 is the main structure of the fuel cell, and the electrode unit 1 is the core component of the fuel cell body 8 that generates current. The catalyst-coated proton exchange membrane (CCM) is the core part of the electrode unit 1 where the electrochemical reaction occurs, while the diffusion layer is used to guide hydrogen and oxygen into the catalyst-coated proton exchange membrane, providing sufficient gas for the electrochemical reaction. The bipolar plates play an important role in the fuel cell, supporting the electrode units, distributing the reaction gases, collecting and conducting current, conducting heat, removing water generated in the reaction, withstanding mechanical stress, and sealing. The electrode unit 1 and the bipolar plates 7 are stacked alternately, with bipolar plates 7 at both ends.

[0030] This novel catalyst-coated proton exchange membrane 4 includes a proton exchange membrane and a catalyst layer coated on both sides of the proton exchange membrane. The proton exchange membrane is the site of the electrochemical reaction and is responsible for conducting protons (H+). + This process simultaneously prevents electron transfer and isolates the anode and cathode reactions. The catalyst layer exhibits high stability and catalytic activity, gently adsorbing hydrogen atoms and desorbing hydrogen gas from its surface. With an overpotential close to zero, it improves reaction efficiency. The catalyst layer on both sides of the proton exchange membrane has the same area.

[0031] The novel diffusion layer 6 has a two-layer structure: a graphite layer 61 and a carbon fiber layer 62. The graphite layer 61 is in contact with the catalyst layer, and the carbon fiber layer 62 is in contact with the bipolar plate 7. The graphite layer 61 and the carbon fiber layer 62 are bonded together to form the diffusion layer 6. The graphite layer 61 is in contact with the catalyst layer 42, which can reduce the contact resistance and ensure that electrons can be smoothly transported out of the catalyst layer. The graphite layer has high conductivity, good chemical stability, high thermal stability, and high mechanical strength, while the carbon fiber layer has high porosity, high conductivity, good mechanical properties, chemical stability, and a hydrophilic / hydrophobic balance. The diffusion layer composed of the graphite layer and the carbon fiber layer ensures the high efficiency and stable operation of the battery. The thickness of the diffusion layer 6 is preferably 200–750 μm. The present invention provides a first flow channel 63 on the carbon fiber layer 62. The first flow channel 63 is used to improve the gas (hydrogen and oxygen) transmission efficiency, reduce the phenomenon of insufficient or excessive local gas, improve the efficiency of electrochemical reaction, and also help to discharge the water generated by the reaction in a timely manner, reducing the accumulation of water in the diffusion layer.

[0032] The first flow channel 63 of this invention is either a straight flow channel or a serpentine flow channel. A straight flow channel is characterized by its simple structure and low flow resistance, while a serpentine flow channel offers advantages such as high reactant gas flow rate, good drainage performance, and good heat dissipation performance. The width of the first flow channel 63 is 0.6–2.2 mm, the flow channel inclination angle is 10–50°, the ridge width is 0.3–1.5 mm, and the ratio of the flow channel width to the ridge width is 1.47–2.0. Preferably, a raised point is provided at the outlet of the first flow channel. The shape of the raised point is not limited, and its width is 20–50% of the flow channel width. The raised point helps to accelerate the outlet gas velocity and promote the diffusion of gas and water.

[0033] Figure 1 This is the first structure of the fuel cell of this utility model. The two sides of the bipolar plate 7 are smooth surfaces, as shown below. Figure 4 As shown, two smooth surfaces are in contact with two adjacent electrode units 1, respectively. Gas transport and drainage are achieved through the first flow channel 63 of the carbon fiber layer 62 of the diffusion layer 6 in the electrode unit 1.

[0034] Figure 2 This is a second structure for the fuel cell of this utility model. In this structure, the two sides of the bipolar plate 7 are respectively provided with second flow channels 74 adapted to the first flow channel 63, such as... Figure 5 As shown. Since both sides of the bipolar plate 7 are provided with second flow channels 74, the second flow channels 74 and the corresponding first flow channels 63 form a new flow channel, through which gas transport and drainage are achieved. The ridge height of the second flow channel 74 gradually decreases with the gas diffusion direction, with a maximum reduction of 5%. This gradual decrease in ridge height reduces gas resistance in the flow channel, allowing the gas to be distributed more evenly across the entire electrode surface, improving the utilization rate of the reactant gas, thereby increasing the battery's current density and output power; it also helps reduce water accumulation in the flow channel and promotes the drainage of reaction-generated water.

[0035] This utility model's bipolar plate 7 is a composite structure of a metal plate and a graphite plate. The anode of the bipolar plate 7 is a graphite plate, and the cathode is a metal plate. Using a graphite plate for the anode ensures corrosion resistance and high conductivity in acidic environments, while using a metal plate for the cathode provides high mechanical strength and good electrical and thermal conductivity. The combination of the two optimizes the overall performance of the battery. Both the graphite plate and the metal plate have good electrical and thermal conductivity, which can improve the heat transfer efficiency by 20% to 30%, stabilize the stack temperature, and significantly reduce the stack thickness compared to a bipolar plate with a single graphite plate.

[0036] The cathode surface of the bipolar plate 7 is coated with an anti-corrosion coating. This coating isolates the metal plate from the electrolyte, preventing oxidation and corrosion of the metal plate in an acidic working environment, reducing performance degradation caused by corrosion, and simultaneously lowering contact resistance and enhancing conductivity. The anti-corrosion coating is at least one of a noble metal coating, a graphite coating, a conductive polymer coating, a metal carbide coating, or a metal oxide coating. Preferably, the metal oxide coating is a cerium oxide coating or a zirconium oxide coating. Cerium oxide and zirconium oxide coatings possess excellent corrosion resistance, high conductivity, good thermal stability, and self-healing capabilities, significantly improving the performance and lifespan of the fuel cell.

[0037] The electrode unit 1 of this invention also includes a pair of encapsulation layers 5, which ensure the sealing and stability of the electrode unit during operation. The catalyst-coated proton exchange membrane 4 is encapsulated within the pair of encapsulation layers 5. The encapsulation layers 5 have openings 54 that expose the effective structure of the catalyst-coated proton exchange membrane 4. The diffusion layer 6 is bonded to the catalyst-coated proton exchange membrane 4 through the openings 54. The encapsulation is preferably a hot-melt type plastic seal.

[0038] The fuel cell body 8 of this invention has an end plate 3 on each side. Located at both ends, the end plates serve to fix and seal the entire battery, and also prevent current leakage, ensuring the safe operation of the fuel cell stack. The fuel cell also includes a pair of current collectors 2, which are attached between the fuel cell body 8 and the end plates 3. These current collectors collect the current generated by the electrode units and transmit it to the external circuit. They also provide mechanical support, maintaining the stability and sealing of the electrode units. Through the synergistic effect of the electrode units, bipolar plates, current collectors, and end plates, this fuel cell can efficiently and stably convert chemical energy into electrical energy, meeting various application requirements.

[0039] The end plate 3 of this utility model is made of at least one of stainless steel, aluminum alloy, polyoxymethylene, and bakelite. Stainless steel has good corrosion resistance, high strength, and durability; aluminum alloy has high strength, corrosion resistance, and good thermal conductivity; polyoxymethylene has excellent mechanical properties and wear resistance; and bakelite has good insulation properties, high temperature resistance, and corrosion resistance. Each of the above-mentioned end plates has its unique advantages, and the appropriate material is selected according to specific application requirements and working environment. The end plate can also be designed with heat dissipation function to help dissipate the heat generated by the battery stack during operation and keep the battery stack operating within a suitable temperature range. Preferably, an air coil flow channel is provided on the end plate for air intake heating and to reduce heat loss at both ends of the battery stack.

[0040] The plastic seal layer 5 of this invention has a first coolant flow channel hole 51, a first hydrogen gas hole 52, and a first air hole 53 at both ends; the end plate 3 has a fourth coolant flow channel hole 31, a fourth hydrogen gas hole 32, and a fourth air hole 33 corresponding to the first coolant flow channel hole 51, the first hydrogen gas hole 52, and the first air hole 53 at both ends; the manifold 2 also has a third coolant flow channel hole 21, a third hydrogen gas hole 22, and a third air hole 23 corresponding to the first coolant flow channel hole 51, the first hydrogen gas hole 52, and the first air hole 53 at both ends. The coolant circulates through the coolant flow channels of the end plate 3, the manifold 2, and the plastic seal layer 5, absorbing and carrying away the heat generated by the battery, thereby maintaining the temperature of the battery stack within a reasonable range, reducing the generation of local hot spots, improving the temperature uniformity of the battery, and ultimately improving the overall performance and lifespan of the fuel cell. Hydrogen gas is introduced from the external supply system into the catalyst layer through hydrogen vents in the end plate 3, the manifold 2, and the sealing layer 5 to participate in the electrochemical reaction, ensuring uniform distribution of hydrogen gas on the catalyst layer surface and improving reaction efficiency. Oxygen is supplied through air vents in the end plate 3, the manifold 2, and the sealing layer 5, which also help drain water generated during the reaction, preventing flooding, maintaining the permeability of the diffusion layer, and ensuring the continuous progress of the reaction. The specific locations of the first coolant flow channel vent 51, the first hydrogen vent 52, and the first air vent 53 are not limited to... Figure 3 As shown, the first coolant flow channel hole 51, the first hydrogen hole 52, and the first air hole 53 are all symmetrically distributed about both ends of the plastic seal layer 5.

[0041] Finally, it should be noted that the above embodiments are merely preferred embodiments of this utility model used to illustrate the technical solutions of this utility model, and are not intended to limit it, nor are they intended to limit the patent scope of this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model. That is to say, any changes or refinements made to the main design concept and spirit of this utility model that are not of substantial significance, but whose technical problems are still consistent with those of this utility model, should be included within the protection scope of this utility model. In addition, the direct or indirect application of the technical solutions of this utility model to other related technical fields are similarly included within the patent protection scope of this utility model.

Claims

1. A fuel cell, characterized by comprising: The fuel cell body (8) comprises a plurality of electrode units (1) and a plurality of bipolar plates (7), the electrode units (1) and the bipolar plates (7) are stacked and spaced apart to form the fuel cell body (8); one end plate (3) is arranged on each side of the fuel cell body (8), and a current collecting plate (2) is arranged between the fuel cell body (8) and the end plate (3). The electrode unit (1) comprises a catalyst coated proton membrane (4) and a pair of diffusion layers (6), and the catalyst coated proton membrane (4) is attached to one diffusion layer (6) on each side. The catalyst coated proton membrane (4) comprises a proton exchange membrane and a catalyst layer coated on both sides of the proton exchange membrane; the diffusion layer (6) has a two-layer structure, one layer is a graphite layer (61), and the other layer is a carbon fiber layer (62); the graphite layer (61) is in contact with the catalyst layer, and the carbon fiber layer (62) is in contact with the bipolar plate (7). The carbon fiber layer (62) is provided with a first flow channel (63).

2. A fuel cell according to claim 1, wherein The first flow channel (63) is one of a straight flow channel or a serpentine flow channel; the flow channel width of the first flow channel (63) is 0.6-2.2 mm, the flow channel inclination angle is 10-50°, the ridge width is 0.3-1.5 mm, and the ratio of the flow channel width to the ridge width is 1.47-2.

0.

3. A fuel cell according to claim 2, wherein The two sides of the bipolar plate (7) are smooth.

4. A fuel cell according to claim 2, wherein The two sides of the bipolar plate (7) are provided with a second flow channel (74) matched with the first flow channel (63), and the ridge height of the second flow channel gradually decreases along the gas diffusion direction, and the maximum decrease is 5%.

5. A fuel cell according to claim 1, wherein The bipolar plate (7) is a composite structure of a metal plate and a graphite plate, the anode of the bipolar plate (7) is a graphite plate, and the cathode is a metal plate; the surface of the cathode of the bipolar plate (7) is coated with a corrosion-resistant coating, and the corrosion-resistant coating is at least one of a noble metal coating, a graphite coating, a conductive polymer coating, a metal carbide, and a metal oxide coating.

6. A fuel cell according to claim 1, wherein The electrode unit (1) further comprises a pair of plastic sealing layers (5), the catalyst coated proton membrane (4) is plastic sealed in the pair of plastic sealing layers (5), the plastic sealing layer (5) is provided with an opening (54) for exposing the effective structure of the catalyst coated proton membrane (4), and the diffusion layer (6) is attached to the catalyst coated proton membrane (4) through the opening (54); the plastic sealing layer (5) is provided with a first cooling liquid flow channel hole (51), a first hydrogen hole (52), and a first air hole (53) at two ends, respectively.

7. A fuel cell according to claim 6, wherein The two ends of the bipolar plate (7) are respectively provided with a second cooling liquid flow channel hole (71), a second hydrogen hole (72), and a second air hole (73) corresponding to the first cooling liquid flow channel hole (51), the first hydrogen hole (52), and the first air hole (53).

8. A fuel cell according to claim 6, wherein The two ends of the end plate (3) are respectively provided with a fourth cooling liquid flow channel hole (31), a fourth hydrogen hole (32), and a fourth air hole (33) corresponding to the first cooling liquid flow channel hole (51), the first hydrogen hole (52), and the first air hole (53).

9. A fuel cell according to claim 8, wherein The two ends of the current collecting plate (2) are respectively provided with a third cooling liquid flow channel hole (21), a third hydrogen hole (22), and a third air hole (23) corresponding to the first cooling liquid flow channel hole (51), the first hydrogen hole (52), and the first air hole (53).

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