A monopolar plate, bipolar plate, stack and fuel cell
By designing a non-uniform throttling section within the fuel cell flow channel, the problems of excessive pressure drop in the flow field and unreasonable distribution of reactant gases were solved, thereby improving the performance and lifespan of the fuel cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA AUTOMOTIVE INNOVATION CORP
- Filing Date
- 2023-03-01
- Publication Date
- 2026-05-12
AI Technical Summary
In existing fuel cell flow field designs, the uniform distribution of throttling structures leads to excessive pressure drop in the flow field, unreasonable distribution of reactant gases, increased parasitic power, and an inability to adapt to dynamic changes during fuel cell operation.
The throttling sections within the flow channels of both monopolar and bipolar plates are designed to be non-uniformly varied, including a combination of contraction, expansion, and connection sections, and are arranged non-uniformly along the fluid flow direction. This increases resource allocation in the downstream region of the flow field and reduces the difference in current density between the upstream and downstream.
It significantly reduces parasitic losses in the flow field, improves the performance of the downstream region of the flow field, stabilizes the working state of the active region, and extends the life of the fuel cell.
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Figure CN116404194B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of fuel cells, in particular to a single polar plate, a bipolar plate, a fuel cell stack and a fuel cell. BACKGROUND
[0002] Proton exchange membrane fuel cell (PEMFC) is a kind of high-efficiency energy conversion device that directly converts chemical energy into electrical energy through hydrogen and oxygen electrochemical reaction. It has become one of the most ideal new energy technologies in the world because it has the characteristics of high energy conversion rate and environmental friendliness, and it is not limited by Carnot cycle in the power generation process. It has broad application prospects and great potential, and is widely used in portable devices, transportation and fixed power generation fields.
[0003] Proton exchange membrane fuel cell is composed of multiple single cells in series, and the core components of each single cell are membrane electrode and bipolar plate. Membrane electrode assembly (MEA) is composed of ion-conducting (mostly hydrogen ion-conducting) membrane, catalytic electrodes (anode and cathode) arranged on both sides of the membrane, and gas diffusion layers (GDL) on both sides of the catalytic electrodes, which provide the working interface of electrochemical reaction. Each membrane electrode assembly and the bipolar plates arranged on both sides (also known as flow field plates or diaphragm plates) together constitute a single cell unit, and the bipolar plate plays a role in separating fuel gas (hydrogen), oxidant and providing access to the membrane electrode surface, and also has the functions of collecting and conducting current, exchanging heat for electrochemical reaction, providing structural support for the membrane electrode assembly, etc.
[0004] During the operation of the fuel cell, hydrogen enters the bipolar plate through the hydrogen inlet manifold, is distributed into the hydrogen flow field through the bipolar plate, diffuses into the gas diffusion layer, and then reaches the anode catalytic electrode surface. Hydrogen ions then pass through the proton membrane to reach the cathode catalytic electrode surface, and electrons pass through the bipolar plate to reach the adjacent single cell cathode. Similarly, the oxidant enters the bipolar plate through the air inlet manifold, is distributed into the air flow field through the bipolar plate, and then reaches the cathode catalytic electrode surface to perform electrochemical reaction. The reaction products and unreacted working medium are collected by the flow field, discharged from the bipolar plate, and then discharged from the fuel cell through the exhaust manifold.
[0005] In order to optimize the mass transfer and drainage of the polar plate flow field, the existing flow channel introduces a throttling structure, which includes a converging section and an expanding section. By utilizing the principle of Venturi tube, a pressure difference is formed between the adjacent two flow channels, realizing three-dimensional flow of the flow field and weakening the ridge groove effect.
[0006] During the operation of a fuel cell, as the electrochemical reaction occurs along the flow direction of the fluid in the flow channel, the reactants are gradually consumed and their concentration gradually decreases; the generated substance, water, gradually accumulates. However, in the existing design, the throttling structure in the entire flow field region is the same structure and is evenly distributed. This not only leads to excessively high pressure drop in the flow field and unreasonable distribution of reactant gases, but also causes problems such as increased parasitic power. Summary of the Invention
[0007] The purpose of this invention is to provide a single plate, a bipolar plate, a fuel cell stack, and a fuel cell that are compatible with the dynamic changes during the operation of a fuel cell, thereby improving the performance of the fuel cell.
[0008] To achieve the above objectives, the following technical solution is provided:
[0009] In a first aspect, a monopolar plate is provided, the monopolar plate comprising a plurality of flow channels spaced apart along a first direction, each flow channel comprising a plurality of throttling sections spaced apart sequentially along the flow direction of fluid within the flow channel, each throttling section comprising a contraction section and an expansion section sequentially connected along the flow direction of fluid within the flow channel, the longitudinal cross-sectional area of the contraction section decreasing sequentially along the flow direction of fluid within the flow channel, and the longitudinal cross-sectional area of the expansion section increasing sequentially along the flow direction of fluid within the flow channel; the longitudinal cross-section is a cross-section perpendicular to the flow direction of fluid within the flow channel; the throttling sections of two adjacent flow channels are staggered.
[0010] In the same flow channel or two adjacent flow channels, along the flow direction of the fluid in the flow channel, the multiple throttling sections are divided into multiple groups, and each group of throttling sections includes multiple throttling sections;
[0011] Along the flow direction of the fluid in the flow channel, the spacing between two adjacent throttling sections in the multiple sets of throttling sections decreases sequentially, and / or the minimum longitudinal cross-sectional area of the throttling sections in the multiple sets of throttling sections decreases sequentially, and / or the length of the throttling sections in the multiple sets of throttling sections decreases sequentially.
[0012] As an alternative to the monopolar plate, the throttling section further includes a connecting section between the contraction section and the expansion section.
[0013] As an alternative to the monopolar plate, the longitudinal cross-sectional area of the connecting section remains unchanged along the flow direction of the fluid in the flow channel.
[0014] As an alternative to the monopolar plate, along the flow direction of the fluid in the flow channel, the length of the contraction section of the multiple sets of throttling sections decreases sequentially, and / or the length of the expansion section of the multiple sets of throttling sections decreases sequentially, and / or the length of the connection section of the multiple sets of throttling sections decreases sequentially.
[0015] As an alternative to the monopolar plate, along the flow direction of the fluid in the flow channel, the length of the contraction section of the same group of throttling sections decreases or remains unchanged in sequence, and / or the length of the expansion section of the same group of throttling sections decreases or remains unchanged in sequence, and / or the length of the connection section of the same group of throttling sections decreases or remains unchanged in sequence.
[0016] As an alternative to the monopolar plate, along the flow direction of the fluid within the flow channel, the spacing between two adjacent throttling sections in the same group of throttling sections decreases sequentially or remains constant; and / or,
[0017] Along the flow direction of the fluid within the flow channel, the minimum longitudinal cross-sectional area of the throttling sections in the same group decreases or remains unchanged sequentially; and / or,
[0018] Along the flow direction of the fluid within the flow channel, the length of the throttling sections in the same group decreases or remains unchanged sequentially.
[0019] As an alternative to the monopolar plate, the flow channel further includes multiple flow sections, the longitudinal cross-sectional area of which remains unchanged along the flow direction of the fluid within the flow channel;
[0020] In the same flow channel, multiple flow sections and multiple throttling sections are sequentially and alternately connected along the flow direction of the fluid within the flow channel.
[0021] In a second aspect, a bipolar plate is provided, comprising a monopolar plate as described in any of the preceding claims.
[0022] Thirdly, a fuel cell stack is provided, including the bipolar plates as described above.
[0023] Fourthly, a fuel cell is provided, comprising the stack described above.
[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0025] Compared to existing technologies, the monopolar and bipolar plates of this invention employ a non-uniform variation design for the throttling section within the flow field. This significantly reduces the overall parasitic losses in the flow field and allows for the allocation of more resources to the downstream region of the flow field, where reactant concentrations are low and product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region and improving fuel cell performance. Simultaneously, it reduces the current density difference between the upstream and downstream surfaces of the membrane electrode, resulting in a more stable and balanced operating state across the entire active region and effectively extending the fuel cell's lifespan.
[0026] The fuel cell stack and fuel cell of the present invention can improve fuel cell performance by applying the above-mentioned bipolar plates. Attached Figure Description
[0027] Fig. 1 This is a schematic diagram of the structure of a single-pole plate in an embodiment of the present invention;
[0028] Fig. 2 This is a schematic diagram illustrating the arrangement of multiple flow channels in an embodiment of the present invention;
[0029] Fig. 3 This is a schematic diagram of the flow channel structure in an embodiment of the present invention.
[0030] Figure label:
[0031] 100. Monopolar plate; 1. Flow channel; 11. Flow section; 12. Throttling section; 121. Contraction section; 122. Expansion section; 123. Connecting section. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0035] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0039] Example 1
[0040] like Figs. 1-3 As shown, this embodiment provides a monopolar plate 100 and a bipolar plate. The bipolar plate includes two monopolar plates 100 fixedly connected. The monopolar plate 100 includes a plurality of flow channels 1 spaced apart along a first direction. The flow channel 1 includes a plurality of flow sections 11 and a plurality of throttling sections 12. In the same flow channel 1, the plurality of flow sections 11 and the plurality of throttling sections 12 are sequentially and alternately connected along the flow direction of the fluid in the flow channel 1. In other words, along the flow direction of the fluid in the flow channel 1, the plurality of throttling sections 12 in the same flow channel 1 are sequentially and spaced apart. The longitudinal cross-sectional area of the flow section 11 remains unchanged along the flow direction of the fluid in the flow channel 1; the throttling section 12 includes a contraction section 121 and an expansion section 122 connected sequentially along the flow direction of the fluid in the flow channel 1. The longitudinal cross-sectional area of the contraction section 121 decreases sequentially along the flow direction of the fluid in the flow channel 1, and the longitudinal cross-sectional area of the expansion section 122 increases sequentially along the flow direction of the fluid in the flow channel 1; the longitudinal section is a section perpendicular to the flow direction of the fluid in the flow channel 1; the throttling sections 12 of two adjacent flow channels 1 are staggered.
[0041] This creates the Venturi effect, forming a pressure difference between two adjacent flow channels 1, achieving three-dimensional flow and reducing the ridge effect; at the same time, the setting of the throttling section 12 will increase the pressure drop of the flow field and improve the mass transfer and drainage performance of the flow field.
[0042] It should be noted that, along the flow direction of the fluid in the flow channel 1, the longitudinal cross-sectional area of the contraction section 121 can decrease gradually or abruptly, as long as the longitudinal cross-sectional area at the inlet end of the contraction section 121 is greater than the longitudinal cross-sectional area at the outlet end of the contraction section 121, and the longitudinal cross-sectional area of the contraction section 121 reaches its minimum at its outlet end; similarly, along the flow direction of the fluid in the flow channel 1, the longitudinal cross-sectional area of the expansion section 122 can increase gradually or abruptly, as long as the longitudinal cross-sectional area at the inlet end of the expansion section 122 is less than the longitudinal cross-sectional area at the outlet end of the expansion section 122, and the longitudinal cross-sectional area of the expansion section 122 reaches its minimum at its inlet end.
[0043] Optionally, the throttling section 12 may also include a connecting section 123 connecting the contraction section 121 and the expansion section 122. Optionally, the longitudinal cross-sectional area of the connecting section 123 remains unchanged along the flow direction of the fluid in the flow channel 1. By providing the connecting section 123, the pressure drop of the flow field can be further increased, thereby improving the mass transfer and drainage performance of the flow field.
[0044] However, during the operation of the fuel cell, as the electrochemical reaction occurs along the fluid flow direction within channel 1, the reactants are gradually consumed, and their concentration gradually decreases; the generated substance, water, gradually accumulates. In the existing design, the throttling sections throughout the entire flow field region have the same structure and are uniformly distributed. This not only leads to excessively high pressure drop in the flow field and unreasonable distribution of reactant gases, but also causes problems such as increased parasitic power.
[0045] To address the aforementioned issues, in this embodiment, the arrangement density of the throttling sections 12 within the flow field region is set to a non-uniform variation. Specifically, within the same flow channel 1 or two adjacent flow channels 1, along the flow direction of the fluid within the flow channel 1, multiple throttling sections 12 are divided into multiple groups, with each group of throttling sections 12 comprising multiple throttling sections 12; along the flow direction of the fluid within the flow channel 1, the spacing between two adjacent throttling sections 12 in the multiple groups of throttling sections 12 decreases sequentially.
[0046] Compared to existing technologies, designing the throttling section 12 within the flow field with non-uniform variation can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field, where the concentration of reactants is low and the amount of generated substances is high. This aligns with the dynamic changes during fuel cell operation, significantly enhancing the performance of the downstream region of the flow field and thus improving the performance of the fuel cell. Simultaneously, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the entire active area more stable and balanced in its operation, effectively extending the working life of the fuel cell.
[0047] Optionally, along the flow direction of the fluid within the flow channel 1, the spacing between two adjacent throttling sections 12 in the same group of throttling sections 12 decreases sequentially. In other words, within the same flow channel 1 or two adjacent flow channels 1, along the flow direction of the fluid within the flow channel 1, the spacing between multiple throttling sections 12 decreases sequentially. This further increases the degree of non-uniformity of the throttling sections 12 within the flow field, further reduces the overall parasitic losses in the flow field, and enhances the performance of the downstream region of the flow field.
[0048] Of course, it can also be set such that the spacing between two adjacent throttling sections 12 in the same group remains unchanged along the flow direction of the fluid in the flow channel 1. Compared with the scheme in which the spacing between two adjacent throttling sections 12 in the same group decreases sequentially along the flow direction of the fluid in the flow channel 1, the degree of non-uniformity variation of the throttling sections 12 is lower, and it is easier to manufacture, but it can still achieve the purpose of reducing the overall parasitic losses of the flow field and enhancing the performance of the downstream region of the flow field.
[0049] This embodiment also provides a fuel cell stack, including the bipolar plate as described above. By applying the bipolar plate, the fuel cell stack of this embodiment can improve fuel cell performance.
[0050] This embodiment also provides a fuel cell, including the stack described above. The fuel cell of this embodiment, by applying the aforementioned stack, has the same beneficial effects as the stack described above.
[0051] Example 2
[0052] The difference between this embodiment and Embodiment 1 is that the minimum longitudinal cross-sectional area of the throttling section 12 in the flow field region is set to be non-uniformly varied. Specifically, along the flow direction of the fluid in the flow channel 1, the minimum longitudinal cross-sectional area of the multiple sets of throttling sections 12 decreases sequentially.
[0053] It should be noted that, since the contraction section 121 and the expansion section 122 are connected sequentially along the flow direction of the fluid in the flow channel 1, the longitudinal cross-sectional area of the contraction section 121 decreases sequentially along the flow direction of the fluid in the flow channel 1, and the longitudinal cross-sectional area of the expansion section 122 increases sequentially along the flow direction of the fluid in the flow channel 1. The connecting section 123 connects the contraction section 121 and the expansion section 122, and the longitudinal cross-sectional area of the connecting section 123 remains unchanged along the flow direction of the fluid in the flow channel 1. Therefore, the longitudinal cross-sectional area of the connecting section 123 is the minimum longitudinal cross-sectional area of the throttling section 12.
[0054] This also enables the non-uniform variation design of the throttling section 12 within the flow field, which can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region of the flow field and improving the performance of the fuel cell. At the same time, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the working state of the entire active area more stable and balanced, and effectively extending the working life of the fuel cell.
[0055] Optionally, along the flow direction of the fluid within the flow channel 1, the minimum longitudinal cross-sectional area of the throttling sections 12 in the same group decreases sequentially. In other words, within the same flow channel 1 or two adjacent flow channels 1, along the flow direction of the fluid within the flow channel 1, the minimum longitudinal cross-sectional area of multiple throttling sections 12 decreases sequentially. This further increases the degree of non-uniformity of the throttling sections 12 within the flow field, further reduces the overall parasitic losses in the flow field, and enhances the performance of the downstream region of the flow field.
[0056] Of course, it can also be set such that the minimum longitudinal cross-sectional area of the throttling sections 12 in the same group remains unchanged along the flow direction of the fluid in the flow channel 1. Compared with the scheme in which the minimum longitudinal cross-sectional area of the throttling sections 12 in the same group decreases sequentially along the flow direction of the fluid in the flow channel 1, the degree of non-uniformity of the throttling sections 12 is lower, and it is easier to manufacture, but it can still achieve the purpose of reducing the overall parasitic losses of the flow field and enhancing the performance of the downstream region of the flow field.
[0057] Example 3
[0058] The difference between this embodiment and Embodiments 1 and 2 is that the length of the throttling section 12 in the flow field region is set to be non-uniformly varied. Specifically, along the flow direction of the fluid in the flow channel 1, the length of the throttling section 12 of the multiple sets of throttling sections 12 decreases sequentially.
[0059] This also enables the non-uniform variation design of the throttling section 12 within the flow field, which can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region of the flow field and improving the performance of the fuel cell. At the same time, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the working state of the entire active area more stable and balanced, and effectively extending the working life of the fuel cell.
[0060] Optionally, along the flow direction of the fluid within the flow channel 1, the lengths of the throttling sections 12 in the same group decrease sequentially. In other words, within the same flow channel 1 or two adjacent flow channels 1, along the flow direction of the fluid within the flow channel 1, the lengths of multiple throttling sections 12 decrease sequentially. This further increases the degree of non-uniform variation of the throttling sections 12 in the flow field, further reduces the overall parasitic losses in the flow field, and enhances the performance of the downstream region of the flow field.
[0061] Of course, it can also be set such that the length of the throttling section 12 in the same group remains unchanged along the flow direction of the fluid in the flow channel 1. Compared with the scheme in which the length of the throttling section 12 in the same group decreases sequentially along the flow direction of the fluid in the flow channel 1, the degree of non-uniformity of the throttling section 12 is lower, and it is easier to manufacture, but it can still achieve the purpose of reducing the overall parasitic loss of the flow field and enhancing the performance of the downstream region of the flow field.
[0062] Optionally, along the flow direction of the fluid in the flow channel 1, the length of the contraction section 121 of the same group of throttling sections 12 decreases or remains unchanged in sequence, and / or the length of the expansion section 122 of the same group of throttling sections 12 decreases or remains unchanged in sequence, and / or the length of the connecting section 123 of the same group of throttling sections 12 decreases or remains unchanged in sequence.
[0063] It is understandable that, since the throttling section 12 includes a contraction section 121, an expansion section 122, and a connecting section 123 connecting the contraction section 121 and the expansion section 122, the length of the throttling section 12 is determined by the lengths of the contraction section 121, the expansion section 122, and the connecting section 123. That is, as long as the length of any one of the contraction section 121, the expansion section 122, and the connecting section 123 decreases, the length of the throttling section 12 will decrease. Similarly, if the lengths of the contraction section 121, the expansion section 122, and the connecting section 123 remain unchanged, the length of the throttling section 12 will remain unchanged.
[0064] When the lengths of the contraction sections 121, expansion sections 122, and connecting sections 123 of the same group of throttling sections 12 decrease sequentially along the flow direction of the fluid in the flow channel 1, the degree of non-uniform variation in the length of the throttling sections 12 in the flow field region is the highest, which can significantly reduce the overall parasitic losses of the flow field and enhance the performance of the downstream region of the flow field.
[0065] When the length of the contraction section 121 of the same group of throttling sections 12 remains unchanged along the flow direction of the fluid in the flow channel 1, and the length of the expansion section 122 of the same group of throttling sections 12 remains unchanged, and the length of the connecting section 123 of the same group of throttling sections 12 remains unchanged, the degree of non-uniform variation of the length of the throttling section 12 in the flow field region is the lowest, which is easy to process. However, it is also possible to design non-uniform variation of the throttling section 12 in the flow field to reduce the overall parasitic loss of the flow field and enhance the performance of the downstream region of the flow field.
[0066] It should be noted that, along the flow direction of the fluid in the flow channel 1, the lengths of the contraction section 121, expansion section 122, and connection section 123 of the same set of throttling sections 12 can be set according to requirements, and are not limited here.
[0067] Example 4
[0068] The difference between this embodiment and embodiments one to three is that the arrangement density of the throttling sections 12 in the flow field region is set to be non-uniformly varied, and the minimum longitudinal cross-sectional area of the throttling sections 12 in the flow field region is set to be non-uniformly varied. Specifically, along the flow direction of the fluid in the flow channel 1, the distance between two adjacent throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially, and the minimum longitudinal cross-sectional area of the throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially.
[0069] This also enables the non-uniform variation design of the throttling section 12 within the flow field, which can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region of the flow field and improving the performance of the fuel cell. At the same time, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the working state of the entire active area more stable and balanced, and effectively extending the working life of the fuel cell.
[0070] Example 5
[0071] The difference between this embodiment and embodiments one to four is that the arrangement density of the throttling sections 12 in the flow field region is set to be non-uniformly varied, and the length of the throttling sections 12 in the flow field region is set to be non-uniformly varied. Specifically, along the flow direction of the fluid in the flow channel 1, the distance between two adjacent throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially, and the length of the throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially.
[0072] This also enables the non-uniform variation design of the throttling section 12 within the flow field, which can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region of the flow field and improving the performance of the fuel cell. At the same time, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the working state of the entire active area more stable and balanced, and effectively extending the working life of the fuel cell.
[0073] Example 6
[0074] The difference between this embodiment and embodiments one to five is that the minimum longitudinal cross-sectional area of the throttling section 12 in the flow field region is set to be non-uniformly varied, and the length of the throttling section 12 in the flow field region is set to be non-uniformly varied. Specifically, along the flow direction of the fluid in the flow channel 1, the minimum longitudinal cross-sectional area of the throttling section 12 of the multiple sets of throttling sections 12 decreases sequentially, and the length of the throttling section 12 of the multiple sets of throttling sections 12 decreases sequentially.
[0075] This also enables the non-uniform variation design of the throttling section 12 within the flow field, which can significantly reduce the overall parasitic losses of the flow field and allocate more resources to the downstream region of the flow field where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, thereby significantly enhancing the performance of the downstream region of the flow field and improving the performance of the fuel cell. At the same time, it reduces the current density difference between the upstream and downstream of the membrane electrode surface, making the working state of the entire active area more stable and balanced, and effectively extending the working life of the fuel cell.
[0076] Example 7
[0077] The difference between this embodiment and embodiments one through six is that the arrangement density of the throttling sections 12 in the flow field region is set to be non-uniform, the minimum longitudinal cross-sectional area of the throttling sections 12 in the flow field region is set to be non-uniform, and the length of the throttling sections 12 in the flow field region is set to be non-uniform. Specifically, along the flow direction of the fluid in the flow channel 1, the distance between two adjacent throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially, the minimum longitudinal cross-sectional area of the throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially, and the length of the throttling sections 12 of the multiple sets of throttling sections 12 decreases sequentially.
[0078] This design also allows for non-uniform variation of the throttling section 12 within the flow field, achieving the highest degree of non-uniform variation. This significantly reduces the overall parasitic losses in the flow field and allocates more resources to the downstream region of the flow field, where the reactant concentration is low and the product accumulation is high. This aligns with the dynamic changes during fuel cell operation, significantly enhancing the performance of the downstream region and thus improving fuel cell performance. Simultaneously, it reduces the current density difference between the upstream and downstream surfaces of the membrane electrode, making the entire active area more stable and balanced, effectively extending the fuel cell's service life.
[0079] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.
Claims
1. A monopolar plate, the monopolar plate (100) comprising a plurality of flow channels (1) spaced apart along a first direction, the flow channels (1) comprising a plurality of throttling sections (12) spaced apart sequentially along the flow direction of fluid within the flow channels (1), the throttling section (12) comprising a contraction section (121) and an expansion section (122) sequentially connected along the flow direction of fluid within the flow channels (1), the longitudinal cross-sectional area of the contraction section (121) decreasing sequentially along the flow direction of fluid within the flow channels (1), and the longitudinal cross-sectional area of the expansion section (122) increasing sequentially along the flow direction of fluid within the flow channels (1); the longitudinal cross-section is a cross-section perpendicular to the flow direction of fluid within the flow channels (1); the throttling sections (12) of two adjacent flow channels (1) are staggered; Its features are, In the same flow channel (1) or two adjacent flow channels (1), along the flow direction of the fluid in the flow channel (1), a plurality of throttling sections (12) are divided into multiple groups, and each group of throttling sections (12) includes a plurality of throttling sections (12); Along the flow direction of the fluid in the flow channel (1), the spacing between two adjacent throttling sections (12) of the multiple sets of throttling sections (12) decreases sequentially, and / or the minimum longitudinal cross-sectional area of the throttling sections (12) of the multiple sets of throttling sections (12) decreases sequentially, and / or the length of the throttling sections (12) of the multiple sets of throttling sections (12) decreases sequentially; The flow channel (1) further includes multiple flow sections (11), the longitudinal cross-sectional area of which remains unchanged along the flow direction of the fluid in the flow channel (1); In the same flow channel (1), multiple flow sections (11) and multiple throttling sections (12) are sequentially and alternately connected along the flow direction of the fluid in the flow channel (1).
2. The monopolar plate according to claim 1, characterized in that, The throttling section (12) also includes a connecting section (123) connecting the contraction section (121) and the expansion section (122).
3. The monopolar plate according to claim 2, characterized in that, The longitudinal cross-sectional area of the connecting section (123) remains unchanged along the flow direction of the fluid in the flow channel (1).
4. The monopolar plate according to claim 2, characterized in that, Along the flow direction of the fluid in the flow channel (1), the length of the contraction section (121) of the multiple sets of throttling sections (12) decreases sequentially, and / or the length of the expansion section (122) of the multiple sets of throttling sections (12) decreases sequentially, and / or the length of the connecting section (123) of the multiple sets of throttling sections (12) decreases sequentially.
5. The monopolar plate according to claim 4, characterized in that, Along the flow direction of the fluid in the flow channel (1), the length of the contraction section (121) of the same group of throttling sections (12) decreases or remains unchanged in sequence, and / or the length of the expansion section (122) of the same group of throttling sections (12) decreases or remains unchanged in sequence, and / or the length of the connection section (123) of the same group of throttling sections (12) decreases or remains unchanged in sequence.
6. The monopolar plate according to claim 1, characterized in that, Along the flow direction of the fluid within the flow channel (1), the spacing between two adjacent throttling sections (12) in the same group decreases or remains unchanged sequentially; and / or, Along the flow direction of the fluid within the flow channel (1), the minimum longitudinal cross-sectional area of the throttling sections (12) in the same group decreases or remains unchanged sequentially; and / or, Along the flow direction of the fluid in the flow channel (1), the length of the throttling section (12) in the same group decreases or remains unchanged in sequence.
7. A bipolar plate, characterized in that, Including the monopolar plate as described in any one of claims 1-6.
8. A fuel cell stack, characterized in that, Including the bipolar plate as described in claim 7.
9. A fuel cell, characterized in that, Includes the fuel cell stack as described in claim 8.