Fuel cell bipolar plate runner and bipolar plate
By designing a periodically varying gas flow channel cross-sectional area in the bipolar plate flow channel of the fuel cell, the problems of uneven gas distribution and poor moisture removal were solved, thereby improving the reaction efficiency and mechanical strength of the fuel cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HUNAN ZHENBANG HYDROGEN ENERGY TECH CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-05-19
AI Technical Summary
Existing bipolar plate flow field designs for fuel cells suffer from uneven gas distribution and poor moisture removal, especially in the throat where flow velocity changes drastically, leading to uneven gas concentration and insufficient mechanical strength.
A bipolar plate flow channel for a fuel cell is designed, wherein the cross-sectional area of the gas flow channel changes periodically along the gas flow direction, including a first wide-diameter region, a gradient region, and a narrow-diameter region connected in sequence. By mirroring the configuration and designing the gradient region, the gas flow rate and drainage performance are optimized.
This achieves uniform distribution and diffusion of gas within the flow channel, enhances the utilization efficiency of reactants, and improves drainage performance within the flow channel, ensuring stable operation of the fuel cell.
Smart Images
Figure CN224264068U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fuel cell technology, specifically to a fuel cell bipolar plate flow channel and bipolar plate. Background Technology
[0002] Bipolar plates are one of the core components of fuel cells (such as proton exchange membrane fuel cells (PEMFC) and alkaline fuel cells (AFC), and their main functions include:
[0003] Conductive: Collects and conducts current, connecting single cells to form a stack.
[0004] Gas delivery: The reaction gas (hydrogen, oxygen or air) is uniformly distributed to the electrode surface through the surface flow field structure (such as grooves, serpentine channels, etc.).
[0005] Drainage: Drain the water generated in the reaction to prevent the electrodes from being "flooded".
[0006] Support structure: Separates individual cells and maintains the mechanical strength of the fuel cell stack.
[0007] Because its surface flow field design is key to achieving gas distribution, it is also known as a "flow field plate". In addition, in some scenarios, bipolar plates may also be commonly referred to as "plates" depending on the material or process, but "flow field plate" is a more accurate professional name for its function.
[0008] Currently, the flow field design schemes applied to bipolar plates of fuel cells are mainly divided into three categories: parallel flow field structure, serpentine flow field structure, and mesh structure.
[0009] Parallel flow field structures are beneficial for the uniform distribution of reactant gases, with large diffusion areas, short channels, small gas assistance, and uniform pressure distribution; however, they are prone to turbulence, which is detrimental to gas diffusion and transport.
[0010] A serpentine flow field structure can avoid this situation, but compared with a parallel flow field, it has a smaller diffusion area, a larger inlet and outlet pressure difference, and greater flow resistance, which can easily cause uneven gas concentration.
[0011] In existing technology, patent CN113745562 adds staggered throat settings to the parallel flow field, effectively enhancing convective mass transfer and suppressing turbulence. Its shortcomings are: the throat abruptly shrinks to a point and then immediately expands, resulting in a short velocity change time for the high-speed airflow passing through the throat; its improvement on gas concentration is limited! Furthermore, the flow channel depth at the throat is reduced, and it has an angular transition; this design also increases the difficulty of manufacturing while resulting in lower mechanical strength of the bipolar plate at that location. Utility Model Content
[0012] The technical problem to be solved by this utility model is to provide a bipolar plate flow channel and bipolar plate for fuel cells with uniform gas distribution and smooth moisture removal.
[0013] The technical solution adopted by this utility model to solve the technical problem is as follows:
[0014] A bipolar plate flow channel for a fuel cell includes a bipolar plate body and a plurality of gas flow channels disposed on the bipolar plate. The cross-sectional area of each gas flow channel changes periodically along the gas flow direction. Each cross-sectional area change period of the gas flow channel includes a first wide-diameter region, a first gradient region, a first narrow-diameter region, a second gradient region, a second wide-diameter region, a third gradient region, a second narrow-diameter region, and a fourth gradient region that are connected in sequence. The cross-sectional area of the first narrow-diameter region is inclined downward along the gas flow direction and has a constant diameter, while the cross-sectional area of the second narrow-diameter region is inclined upward along the gas flow direction and has a constant diameter.
[0015] In one embodiment, the first gradient region, the first narrow diameter region, the second gradient region, and the third gradient region, the second narrow diameter region, and the fourth gradient region are mirror images of each other.
[0016] In one implementation, the first width region and the second width region are not on the same horizontal line.
[0017] In one embodiment, the cross-sectional area of the first wide-diameter region is a direct-flow channel along the gas flow direction.
[0018] In one embodiment, the cross-sectional area of the first gradient region is arc-shaped along the gas flow direction and its diameter gradually decreases.
[0019] In one embodiment, the cross-sectional area of the second gradient region is arc-shaped along the gas flow direction and its diameter gradually increases.
[0020] In one embodiment, the cross-sectional area of the second wide-diameter region forms a direct-flow channel along the gas flow direction.
[0021] In one embodiment, the cross-sectional area of the third gradient zone is arc-shaped along the gas flow direction and its diameter gradually decreases.
[0022] In one embodiment, the cross-sectional area of the fourth gradient zone is arc-shaped along the gas flow direction and its diameter gradually increases.
[0023] The technical solution adopted by this utility model to solve another aspect of its technical problem is:
[0024] A bipolar plate is provided, which has a fuel cell bipolar plate flow channel as described in any of the above-mentioned schemes, wherein the fuel cell bipolar plate flow channel is disposed on the bipolar plate.
[0025] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0026] This invention utilizes a bipolar plate body and several gas channels disposed on the bipolar plate. The cross-sectional area of each gas channel changes periodically along the gas flow direction. Each cycle of cross-sectional area change in the gas channel includes a first wide-diameter region, a first gradient region, a first narrow-diameter region, a second gradient region, a second wide-diameter region, a third gradient region, a second narrow-diameter region, and a fourth gradient region, which are connected sequentially. The cross-sectional area of the first narrow-diameter region slopes downward along the gas flow direction and has a constant diameter, while the cross-sectional area of the second narrow-diameter region slopes upward along the gas flow direction and has a constant diameter. Thus, this invention can change the gas flow velocity within the channels, enhance the gas diffusion rate to the diffusion layer, and facilitate the uniform distribution and diffusion of gas to the gas diffusion layer of the membrane electrode for reaction with the catalyst. This allows for more efficient utilization of the reactants in the gas and also enhances the drainage performance within the channels. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the bipolar plate structure of this utility model;
[0028] Figure 2 This utility model Figure 1 A schematic diagram of part A in the diagram.
[0029] Figure 3 This is a schematic diagram of the flow channel structure of this utility model;
[0030] Figure 4 This utility model Figure 1 A schematic diagram of the structure of a single flow channel.
[0031] In the figure: 10. Gas flow channel, 11. First wide diameter region, 12. First gradient region, 13. First narrow diameter region, 14. Second gradient region, 15. Second wide diameter region, 16. Third gradient region, 17. Second narrow diameter region, 18. Fourth gradient region. Detailed Implementation
[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0033] It should be noted that the bipolar plate includes an air inlet, an air inlet passage, an air outlet, a flow guide area, a flow channel area, and an air outlet; the flow channel area contains several flow channels.
[0034] Example 1
[0035] like Figure 1-4As shown, this embodiment includes a bipolar plate body and a plurality of gas channels 10 disposed on the bipolar plate. The cross-sectional area of each gas channel 10 changes periodically along the gas flow direction. Each cross-sectional area change period of the gas channel 10 includes a first wide diameter region 11, a first gradient region 12, a first narrow diameter region 13, a second gradient region 14, a second wide diameter region 15, a third gradient region 16, a second narrow diameter region 17, and a fourth gradient region 18 connected in sequence. In this embodiment, the first gradient region 12, the first narrow diameter region 13, and the second gradient region 14 are mirror images of the third gradient region 16, the second narrow diameter region 17, and the fourth gradient region 18, and the first wide diameter region 11 and the second wide diameter region 15 are not on the same horizontal line; that is, from the perspective of cross-sectional area, the first wide diameter region 11 is located above one end of the second wide diameter region 15.
[0036] The cross-sectional area of the first wide diameter region 11 is a direct flow channel along the gas flow direction. In this embodiment, the first wide diameter region 11 is cylindrical. It should be noted that under the same operating conditions (same pressure / flow rate and temperature), the larger the flow channel area, the lower the flow velocity. When the gas passes through the first wide diameter region 11, its flow velocity is the lowest because the first wide diameter region 11 is in the range with the largest flow channel area in the entire flow channel cycle.
[0037] The cross-sectional area of the first gradient region 12 is arc-shaped along the gas flow direction and the diameter gradually decreases; in this embodiment, the cross-sectional area of the first gradient region 12 is arc-shaped along the gas flow direction and the diameter gradually decreases; and the maximum diameter end of the first gradient region 12 is connected to the first wide diameter region 11, and the minimum diameter of the first gradient region 12 is one-half the diameter of the first wide diameter region 11.
[0038] Therefore, after the gas from the first wide diameter region 11 enters the first gradual transition region 12, the flow velocity begins to increase. As the diameter of the first wide diameter region 11 gradually decreases, the gas flow velocity increases, and the force exerted on the two side walls of the first wide diameter region 11 also increases accordingly, until it enters the narrow diameter region 13.
[0039] The cross-sectional area of the first narrow diameter region 13 is inclined downward along the gas flow direction and the diameter remains unchanged. In this embodiment, the cross-sectional area of the first narrow diameter region 13 is inclined downward along the gas flow direction (from left to right) and the diameter remains unchanged. The front end of the first narrow diameter region 13 is connected to the minimum diameter in the first gradient region 12, that is, the diameter of the first narrow diameter region 13 is one-half the diameter of the first wide diameter region 11.
[0040] Therefore, when the gas in the first gradient zone 12 enters the first narrow diameter zone 13, the gas velocity in the first narrow diameter zone 13 reaches its maximum because the cross-sectional area of the first narrow diameter zone 13 is inclined downward along the gas flow direction and the diameter remains unchanged; at the same time, the diameter of the first narrow diameter zone 13 is also the smallest.
[0041] The cross-sectional area of the second gradient region 14 is arc-shaped along the gas flow direction and the diameter gradually increases. In this embodiment, the cross-sectional area of the second gradient region 14 is arc-shaped along the gas flow direction and the diameter gradually increases; and the smallest diameter end of the first gradient region 12 is connected to the first narrow diameter region 13, and the smallest diameter of the second gradient region 14 is one-half the diameter of the first wide diameter region 11.
[0042] The cross-sectional area of the second wide-diameter region 15 is a direct-flow channel along the gas flow direction; in this embodiment, the second wide-diameter region 15 is cylindrical; the front end of the second wide-diameter region 15 is connected to the maximum diameter end of the second gradient region 14; thus, after passing through the second gradient region 14, the gas enters the second wide-diameter region 15; since the gas enters the second gradient region 14 of the same diameter after passing through the first narrow-diameter region 13 for a short period of time, the gas flow velocity also decreases as the area of the second gradient region 14 increases. After passing through the second gradient region 14, the gas enters the same second gradient region 14 as the first gradient region 11, at which point the gas flow velocity reaches its minimum.
[0043] The cross-sectional area of the third gradient region 16 is arc-shaped along the gas flow direction and the diameter gradually decreases; in this embodiment, the cross-sectional area of the third gradient region 16 is arc-shaped along the gas flow direction and the diameter gradually decreases; and the end of the third gradient region 16 with the largest diameter is connected to the end of the second wide diameter region 15, and the minimum diameter of the third gradient region 16 is half the diameter of the second wide diameter region 15.
[0044] Therefore, after the gas enters the third gradient region 16 from the second wide diameter region 15, the flow velocity begins to increase. As the diameter of the third gradient region 16 gradually decreases, the gas flow velocity becomes larger and larger, and the force on the two side walls of the third gradient region 16 also increases accordingly, until it enters the second narrow diameter region 17.
[0045] The cross-sectional area of the second narrow diameter region 17 is inclined upward along the gas flow direction and the diameter remains unchanged; in this embodiment, the front end of the second narrow diameter region 17 is connected to the minimum diameter in the third gradient region 16; the diameter of the second narrow diameter region 17 is half the diameter of the second wide diameter region 15.
[0046] Therefore, when the gas in the third gradient zone 16 enters the second narrow diameter zone 17, the cross-sectional area of the second narrow diameter zone 17 is inclined downward along the gas flow direction and the diameter remains unchanged; at the same time, the diameter of the second narrow diameter zone 17 is also the smallest. Therefore, the gas flow velocity entering the second narrow diameter zone 17 reaches the maximum.
[0047] The cross-sectional area of the fourth gradient region 18 is arc-shaped along the gas flow direction and the diameter gradually increases; in this embodiment, the cross-sectional area of the fourth gradient region 18 is arc-shaped along the gas flow direction and the diameter gradually increases; and the minimum diameter end of the fourth gradient region 18 is connected to the end of the second narrow diameter region 17, and the minimum diameter of the second narrow diameter region 17 is half the diameter of the first wide diameter region 11.
[0048] After passing through the short-length second narrow-diameter zone 17, the gas enters the same fourth gradual transition zone 18 connected to it. At this time, the flow channel area increases from small to large, and the gas flow velocity also decreases from high to low.
[0049] Thus, the entire flow channel circulates continuously, with the gas flow rate fluctuating between fast and slow. Consequently, the flow channel of this application can change the gas flow rate within the flow channel, enhancing the gas diffusion rate to the diffusion layer, which is beneficial for the gas to be evenly distributed and diffused to the gas diffusion layer of the membrane electrode to react with the catalyst. This allows for more efficient and full utilization of the reactants in the gas, while also enhancing the drainage performance within the flow channel.
[0050] Furthermore, fuel cells require the continuous consumption of hydrogen and oxygen ions from the gas within the flow channel during operation. However, the purity of hydrogen or oxygen in the supplied hydrogen and air cannot reach 100% (especially since oxygen ions are drawn from the cathode flow channel). This causes the gas concentration within the flow channel to vary from inlet to outlet, resulting in an uneven distribution near the outlet. Simultaneously, the generation of liquid water within the flow channel during fuel cell operation hinders gas flow and diffusion, preventing sufficient reactants (hydrogen or oxygen ions) from reaching certain areas of the fuel cell and thus affecting the stack's power generation efficiency. This application effectively alleviates this situation, resulting in a more uniform gas distribution and smoother moisture removal.
[0051] Example 2
[0052] A bipolar plate is provided with the fuel cell bipolar plate flow channel described in Embodiment 1 above, wherein the fuel cell bipolar plate flow channel is disposed on the bipolar plate.
[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the technical solutions of this utility model have 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of this utility model.
Claims
1. A bipolar plate flow channel for a fuel cell, comprising a bipolar plate body and a plurality of gas flow channels (10) disposed on the bipolar plate, wherein the cross-sectional area of each gas flow channel (10) varies periodically along the gas flow direction; characterized in that: Each cross-sectional area change cycle of the gas flow channel (10) includes a first wide diameter region (11), a first gradient region (12), a first narrow diameter region (13), a second gradient region (14), a second wide diameter region (15), a third gradient region (16), a second narrow diameter region (17), and a fourth gradient region (18) connected in sequence. The cross-sectional area of the first narrow diameter region (13) is inclined downward along the gas flow direction and its diameter remains unchanged. The cross-sectional area of the second narrow diameter region (17) is inclined upward along the gas flow direction and its diameter remains unchanged.
2. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The first gradient region (12), the first narrow diameter region (13), the second gradient region (14) are mirror images of the third gradient region (16), the second narrow diameter region (17), and the fourth gradient region (18).
3. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The first wide diameter region (11) and the second wide diameter region (15) are not on the same horizontal line.
4. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the first wide diameter region (11) is a direct current channel along the gas flow direction.
5. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the first gradient region (12) is arc-shaped along the gas flow direction and the diameter gradually decreases.
6. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the second gradient region (14) is arc-shaped along the gas flow direction and its diameter gradually increases.
7. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the second wide diameter region (15) is a direct current channel along the gas flow direction.
8. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the third gradient region (16) is arc-shaped along the gas flow direction and its diameter gradually decreases.
9. The fuel cell bipolar plate flow channel according to claim 1, characterized in that: The cross-sectional area of the fourth gradient region (18) is arc-shaped along the gas flow direction and its diameter gradually increases.
10. A bipolar plate, characterized in that: The flow channel includes the fuel cell bipolar plate as described in any one of claims 1-9.