A fuel cell bipolar plate and its gas diffusion method and application

Abstract

The present application relates to the technical field of fuel cell, and discloses a fuel cell bipolar plate, a gas diffusion method and application thereof, which comprises a cathode plate and an anode plate. The inlet and outlet of the flow channel groove of the bipolar plate are alternately closed and opened, namely, the outlet corresponding to the inlet open flow channel is closed, and the outlet corresponding to the inlet closed flow channel is open. The ridge plane of the bipolar plate has an inclination angle, and small grooves are arranged at intervals. The gas is forced to enter the carbon paper of the gas diffusion layer due to the pressure difference and penetrates into the adjacent flow channel, which increases the direct contact area between the gas diffusion layer and the gas, is beneficial to the more uniform distribution of the gas in the membrane electrode, and is helpful to the discharge of the generated water in the cathode of the fuel cell, thereby improving the performance of the fuel cell. In addition, the design of the groove increases the frictional resistance of the surface of the bipolar plate, thereby avoiding the displacement between the bipolar plate and the membrane electrode.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell bipolar plate, its gas diffusion method, and its application. Background Technology

[0002] The bipolar plate is a crucial component of a fuel cell. It not only provides the necessary mechanical support and electrical conductor connections for the membrane electrode assembly (MEA), ensuring efficient current collection and transmission, but also plays a vital role in gas distribution. The flow channels of the bipolar plate ensure the delivery of hydrogen and oxygen to the catalytic layer of the MEA and are responsible for maintaining the continuity and consistency of gas flow. Achieving uniform distribution of hydrogen and oxygen through a well-designed flow channel system optimizes the chemical reaction efficiency of the fuel cell and improves energy conversion rate, which is essential for the chemical reaction process in the fuel cell.

[0003] Furthermore, the gas distribution function of the bipolar plates helps prevent excessive accumulation or deficiency of gas in localized areas, avoiding performance degradation or the formation of localized hot spots. Therefore, the gas distribution design of the bipolar plates is crucial for achieving efficient, stable, and long-term operation of fuel cells.

[0004] In addition, bipolar plates are responsible for thermal and water management, ensuring uniform temperature and humidity distribution during battery stack operation, preventing overheating and moisture buildup, thereby maintaining battery stability and extending service life. Therefore, the material selection and structural design of bipolar plates play a decisive role in their insulation performance and overall durability. Summary of the Invention

[0005] The purpose of this invention is to provide a fuel cell bipolar plate that helps to promote uniform gas distribution, and to provide at least a beneficial option or create conditions for solving one or more technical problems existing in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A gas diffusion method for a fuel cell bipolar plate utilizes a through groove on the ridge plane of the flow channel to connect two adjacent flow channel grooves on the same plate. The reactant gas enters from one of the two adjacent flow channel grooves and flows out from the other through the flow channel ridge under the action of pressure difference. At the same time, under the action of pressure difference, the reactant gas is forced into the gas diffusion layer and penetrates into the adjacent flow channel grooves, thereby carrying away the water generated in the membrane electrode.

[0008] More preferably, the channels are evenly distributed on the ridge plane of the flow channel, and the gas flow direction of the channels is along the gas flow direction in the flow channel grooves of two adjacent plates, so as to provide uniformity of gas flow.

[0009] More preferably, the ridge plane of the flow channel ridge is set as an inclined plane with one side higher and the other side lower, the reaction gas enters from the higher side and flows out from the lower side, so as to improve the uniformity of gas diffusion and reduce the contact resistance.

[0010] More preferably, the gas diffusion layer is subjected to hydrophilic and hydrophobic treatment, the side close to the bipolar plate is subjected to hydrophilic treatment, and the side far from the bipolar plate is subjected to hydrophobic treatment, so as to improve the removal of generated water in the cathode of the fuel cell.

[0011] In another aspect, the present application provides a fuel cell bipolar plate, comprising a cathode plate and an anode plate assembled together, and a gas diffusion layer, a catalyst layer and a membrane electrode arranged between the cathode plate and the anode plate; wherein the cathode plate and the anode plate each have a plurality of plate flow channel grooves, each of the plate flow channel grooves extending from an inlet end to an outlet end of the plate; the plate flow channel grooves include first plate flow channel grooves with an open inlet end and a closed outlet end, and second plate flow channel grooves with a closed inlet end and an open outlet end, the first plate flow channel grooves and the second plate flow channel grooves being alternately distributed; adjacent plate flow channel grooves are separated by a flow channel ridge, and a through groove is arranged on the ridge plane of the flow channel ridge to pass through the adjacent plate flow channel grooves; in operation, the reaction gas enters from one of the two adjacent plate flow channel grooves and flows out from the other plate flow channel groove across the flow channel ridge under the action of pressure difference.

[0012] More preferably, the through grooves are uniformly distributed on the ridge plane of the flow channel ridge, and the through grooves on both sides of the same plate flow channel groove are symmetrical to each other.

[0013] More preferably, the through groove is an inclined groove, the gas inlet of the inclined groove is arranged close to the inlet end, and the gas outlet of the inclined groove is arranged close to the outlet end.

[0014] More preferably, the ridge plane is an inclined plane, and the side where the gas flow enters is higher and the side where the gas flow flows out is lower.

[0015] More preferably, the gas diffusion layer is provided with a hydrophilic layer and a hydrophobic layer on both sides respectively, the side close to the bipolar plate is provided with a hydrophilic layer, and the side far from the bipolar plate is provided with a hydrophobic layer.

[0016] In another aspect, the present application also provides a fuel cell having the fuel cell bipolar plate as described above.

[0017] The present application adopts the technical solutions as described above, and has at least the following beneficial effects.

[0018] Firstly, in the present application, the gas needs to pass through the through groove on the ridge to enter the adjacent flow channel, which increases the direct contact area between the gas diffusion layer and the gas, facilitates the gas to enter the gas diffusion layer, and makes the gas distribution in the membrane electrode more uniform.

[0019] Secondly, in the present application, the contact area between the air flow field and the gas diffusion layer is increased, and the water generated by the cathode is more easily carried away by the air, which is beneficial to the drainage of the fuel cell stack and avoids water flooding in the fuel cell.

[0020] Thirdly, in the present application, the small grooves on the flow channel of the bipolar plate increase the friction of the plate, which is beneficial to the assembly of the fuel cell stack, avoids displacement between the membrane electrode and the bipolar plate, and is beneficial to the improvement of the performance of the fuel cell.

[0021] Fourthly, in the present application, the design of the flow channel ridge improves the contact effect between the bipolar plate and the gas diffusion layer, and reduces the contact resistance between the plate and the gas diffusion layer. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a schematic diagram of the fuel cell bipolar plate in the embodiment of the present application.

[0023] Figure 2 FIG. 2 is a three-dimensional schematic diagram of the fuel cell bipolar plate in the embodiment of the present application.

[0024] Figure 3 FIG. 3 is a schematic diagram of the groove of the ridge of the fuel cell bipolar plate in the embodiment of the present application.

[0025] Figure 4 FIG. 4 is a schematic diagram of the gas flow in the flow channel of the fuel cell bipolar plate in the embodiment of the present application, and the arrow represents the direction of the air flow.

[0026] Figure 5 FIG. 5 is a schematic diagram of the gas flow in the fuel cell in the embodiment of the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1: cathode plate, 2: anode plate, 3: plate flow channel groove, 4: inlet end, 5: outlet end, 6: flow channel ridge, 7: gas diffusion layer, 8: exchange membrane, 9: catalyst layer.

[0029] 3-1: first plate flow channel groove, 3-2: second plate flow channel groove.

[0030] 6-1: ridge plane, 6-2: through groove. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application will be further described below in conjunction with the drawings of the specification, so that the technical solutions of the present application and their beneficial effects are more clear and explicit. The description of the embodiments below by referring to the drawings is exemplary and is intended to explain the present application, but cannot be understood as a limitation of the present application.

[0032] Additional aspects and advantages of the present application will become apparent in the following description section, or will be understood by those skilled in the art through the practice of the present application.

[0033] The present application provides a gas diffusion method for fuel cell bipolar plates, which is based on the principle of using through-slots on the ridge plane of flow channel ridges to connect two adjacent flow channel grooves on the same plate, and the reaction gas enters one of the two adjacent flow channel grooves and flows out from the other one across the flow channel ridges under the action of pressure difference; at the same time, the reaction gas is forced to enter the gas diffusion layer and penetrate into the adjacent flow channel groove under the action of pressure difference, and thus the water generated in the membrane electrode is removed.

[0034] In some embodiments, the through-slots are uniformly distributed on the ridge plane of the flow channel ridges, and the gas flow direction of the through-slots follows the gas flow direction of the two adjacent flow channel grooves to provide uniformity of gas flow.

[0035] In some embodiments, the ridge plane of the flow channel ridges is set as an inclined plane with one side higher and the other side lower, the reaction gas enters the higher side and flows out from the lower side, to improve the uniformity of gas diffusion and reduce the contact resistance.

[0036] In some embodiments, the gas diffusion layer of the fuel cell bipolar plate is treated with hydrophilic and hydrophobic treatment, the side close to the bipolar plate is treated with hydrophilic treatment, and the side far from the bipolar plate is treated with hydrophobic treatment, to improve the removal of water generated in the cathode of the fuel cell. Embodiments

[0037] Reference Figures 1-5 As shown in the figure, a fuel cell bipolar plate includes a cathode plate 1 and an anode plate 2 assembled together, and a gas diffusion layer 7, a catalyst layer 9 and an exchange membrane 8 are arranged between the cathode plate 1 and the anode plate 2; the cathode plate 1 and the anode plate 2 each have a plurality of flow channel grooves 3, and each flow channel groove 3 extends from an inlet end 4 to an outlet end 5 of the plate; the flow channel grooves 3 include first flow channel grooves 3-1 with an open inlet end 4 and a closed outlet end, and second flow channel grooves 3-2 with a closed inlet end and an open outlet end, and the first flow channel grooves 3-1 and the second flow channel grooves 3-2 are alternately arranged; adjacent flow channel grooves 3 are separated by flow channel ridges 6, and through-slots 6-2 are arranged on the ridge plane 6-1 of the flow channel ridges 6 to pass through the adjacent flow channel grooves 3; the ridge plane 6-1 is an inclined plane, and the side where the gas flow enters is higher and the side where the gas flow flows out is lower.

[0038] When the fuel cell is in operation, the reaction gas enters the stack from the bipolar plate flow channel groove 3 with the inlet end opening. Since the outlet of the bipolar plate flow channel groove 3 is closed, the gas is forced to enter the carbon paper of the gas diffusion layer 7 and penetrate into the adjacent bipolar plate flow channel groove. The angle of the ridge plane 6-1 and the through groove 6-2 opened on the ridge plane 6-1 help the gas transfer. The pressure difference between the two adjacent bipolar plate flow channel grooves helps the gas flow to the adjacent bipolar plate flow channel groove and more easily carries away the water generated in the membrane electrode. Since the outlet corresponding to the inlet end closed bipolar plate flow channel groove 3-2 is open, the remaining gas finally flows out from this groove.

[0039] It should be noted that the size of the angle of the ridge plane 6-1, and the interval distance and depth of the through groove 6-2 are determined by actual product through limited experiments, which is the ordinary technical knowledge mastered by those skilled in the art. In some embodiments, the ridge plane 6-1 can be a plane, and the through groove 6-2 can be omitted, which is not limited to the present embodiment.

[0040] Compared with the prior art, in the present application, since the reaction gas needs to pass through the gas diffusion layer 7 to enter the adjacent bipolar plate flow channel groove, the direct contact area of the reaction gas and the gas diffusion layer 7 is increased, which is beneficial to the more uniform distribution of the gas in the membrane electrode, and can reduce the gas consumption. Through comparative test, the air consumption of the fuel cell in the present application is reduced by 10% at the same power. At the same time, since the contact area of the air and the gas diffusion layer is increased, it is beneficial to the air to carry away the water generated by the reaction, which is beneficial to the drainage of the stack and avoids the waterlogging in the battery. In addition, since the design of the through groove 6-2 increases the frictional resistance of the surface of the bipolar plate, it avoids the displacement between the bipolar plate and the membrane electrode, which is beneficial to improve the performance of the fuel cell.

[0041] In some embodiments, the side of the gas diffusion layer 7 close to the bipolar plate is hydrophilic treated, and the side away from the bipolar plate is hydrophobic treated, which is more conducive to the generated water in the cathode of the fuel cell to be discharged, and can avoid the waterlogging of the membrane electrode.

[0042] In addition, it should be noted that in the description of the present application, for the orientation words, such as the terms "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation and positional relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and cannot be understood as indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific protection scope of the present application.

[0043] In addition, the terms "first", "second", "third", etc. are used herein for descriptive purposes only and should not be construed as indicating or implying relative importance or an ordered sequence. Thus, use of "first" and / or "second" features in the description herein indicates that at least one of the two features can be included in a given implementation, and that the number of such features can be more than two unless specifically stated otherwise.

[0044] In the present application, unless otherwise specified and limited, the terms "assembly", "connection", "linkage" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection; can be direct connection, can also be connected through intermediate medium, can be internal connection of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the present application, unless otherwise specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or the first feature and the second feature are not in direct contact but are in contact through another feature between them. Moreover, "on", "under" and "above" of the first feature to the second feature includes that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than the height of the second feature. "On", "under" and "below" of the first feature to the second feature includes that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is lower than the height of the second feature.

[0046] Through the above description of structure and principle, those skilled in the art should understand that the present application is not limited to the above specific embodiments, and any improvement and replacement of the technology known in the art based on the present application falls within the protection scope of the present application, and the protection scope of the present application should be limited by the claims and their equivalents. The parts not described in the specific embodiments are all prior art or common knowledge.

Claims

1. A fuel cell bipolar plate comprising a cathode plate and an anode plate assembled together, with a gas diffusion layer, a catalyst layer and a membrane electrode provided between the cathode plate and the anode plate; characterized in that, The cathode plate and the anode plate each have a plurality of plate flow channel grooves, each of which extends from an inlet end to an outlet end of the plate; the plate flow channel grooves include first plate flow channel grooves with an inlet end opening and an outlet end closure, and second plate flow channel grooves with an inlet end closure and an outlet end opening, the first plate flow channel grooves and the second plate flow channel grooves being alternately arranged; adjacent plate flow channel grooves are separated by a flow channel ridge, and a through groove is arranged on a ridge plane of the flow channel ridge to pass through the adjacent plate flow channel grooves; the through groove is an inclined groove, with a gas inlet of the inclined groove arranged close to the inlet end and a gas outlet of the inclined groove arranged close to the outlet end; the ridge plane is an inclined plane, with the side where the gas enters being higher and the side where the gas exits being lower; during operation, the reaction gas enters one of the two adjacent plate flow channel grooves and exits the other one by crossing the flow channel ridge under the action of a pressure difference.

2. A fuel cell bipolar plate according to claim 1, wherein The through grooves are uniformly distributed on the ridge plane of the flow channel ridge, and the through grooves on both sides of the same plate flow channel groove are mutually symmetrical.

3. A fuel cell bipolar plate according to claim 1, wherein The gas diffusion layer is provided with a hydrophilic layer and a hydrophobic layer on both sides, respectively, with the hydrophilic layer arranged on the side close to the bipolar plate and the hydrophobic layer arranged on the side away from the bipolar plate.

4. A fuel cell characterized by comprising: A fuel cell bipolar plate as claimed in any one of claims 1-3.

5. A method of gas diffusion for a fuel cell bipolar plate, characterized by, Based on the fuel cell bipolar plate as claimed in claim 1, the through groove on the ridge plane of the flow channel ridge is used to connect two adjacent plate flow channel grooves on the same plate, and the reaction gas enters one of the two adjacent plate flow channel grooves and exits the other one by crossing the flow channel ridge under the action of a pressure difference; at the same time, under the action of the pressure difference, the reaction gas is forced to enter the gas diffusion layer and penetrate into the adjacent plate flow channel groove, thereby taking away the water generated in the membrane electrode.

6. A method of gas diffusion for a fuel cell bipolar plate according to claim 5, wherein The through grooves are uniformly distributed on the ridge plane of the flow channel ridge, and the gas flow direction of the through groove follows the gas flow direction in the two adjacent plate flow channel grooves, thereby improving the uniformity of gas flow.

7. The method of claim 5, wherein the gas diffusion layer is a bipolar plate of a fuel cell. The ridge plane of the flow channel ridge is arranged as an inclined plane with one side being higher and the other side being lower, with the side where the reaction gas enters being higher and the side where the reaction gas exits being lower, thereby improving the uniformity of gas diffusion and reducing the contact resistance.

8. The method of claim 5, wherein the gas diffusion layer is a bipolar plate of a fuel cell. The gas diffusion layer is subjected to hydrophilic and hydrophobic treatment, with the side close to the bipolar plate being subjected to hydrophilic treatment and the side away from the bipolar plate being subjected to hydrophobic treatment, thereby improving the discharge of generated water in the cathode of the fuel cell.

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