fuel cell bipolar plates

Abstract

This invention provides a fuel cell bipolar plate, comprising: a plate body; a flow channel disposed on the plate body, the flow channel further comprising an inlet and an outlet, and a plurality of first flow channels and a plurality of second flow channels disposed between the inlet and the outlet. The plurality of second flow channels are located downstream of the plurality of first flow channels in the flow direction of the flow channel, and the plurality of first flow channels and the plurality of second flow channels are interconnected, wherein the number of first flow channels is greater than the number of second flow channels. The technical solution of this application effectively solves the problem in related technologies where the membrane electrode at the inlet of the fuel cell bipolar plate is relatively dry, resulting in low power generation efficiency of the fuel cell.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically, to a fuel cell bipolar plate. Background Technology

[0002] A fuel cell is a power generation device that directly converts the chemical energy in fuel and oxidant into electrical energy through an electrochemical reaction. It has the advantages of high energy conversion rate, no pollution, and low noise.

[0003] Bipolar plates are an important component of fuel cells. Each set of bipolar plates includes a cathode plate and an anode plate. The air flow channel is designed on the cathode plate, and the hydrogen flow channel is designed on the anode plate.

[0004] The flow channel performs multiple functions, including uniformly distributing gaseous reactants and purging out generated water. During fuel cell operation, the water generated by the reaction is driven towards the flow channel outlet by the reactant gas flow. Therefore, the amount of liquid water in the flow channel and gas diffusion layer gradually increases from the inlet to the outlet.

[0005] In related technologies, in order to increase the air velocity in the flow channel, the air velocity at the inlet is increased. This results in the membrane electrode at the inlet being drier, leading to lower power generation efficiency of the fuel cell. Summary of the Invention

[0006] The main objective of this invention is to provide a fuel cell bipolar plate to solve the problem that the membrane electrode at the inlet of the fuel cell bipolar plate in the related art is relatively dry, resulting in low power generation efficiency of the fuel cell.

[0007] To achieve the above objectives, the present invention provides a fuel cell bipolar plate, comprising: a plate body; a flow channel disposed on the plate body, the flow channel further comprising an inlet and an outlet, the flow channel further comprising a plurality of first flow channels and a plurality of second flow channels disposed between the inlet and the outlet, the plurality of second flow channels being located downstream of the plurality of first flow channels in the flow direction of the flow channel, and the plurality of first flow channels and the plurality of second flow channels being interconnected, wherein the number of first flow channels is greater than the number of second flow channels.

[0008] Furthermore, the fuel cell bipolar plate includes a first connecting strip located on the plate body. The first connecting strip is located between a plurality of first flow channels and a plurality of second flow channels. The first flow channels are direct flow channels, and the first connecting strip is inclined relative to the first flow channels.

[0009] Furthermore, the flow channel also includes multiple third flow channels disposed between the inlet and the outlet, the number of which is less than the number of second flow channels.

[0010] Furthermore, the fuel cell bipolar plate includes a second connecting band located on the plate body. The second connecting band is located between a plurality of second flow channels and a plurality of third flow channels. The second connecting band is relative to the first flow channel. The second flow channel includes a first flow channel segment, a second flow channel segment, and a third flow channel segment. The third flow channel segment is arranged adjacent to the second connecting band, and the first connecting band is arranged adjacent to the first flow channel segment.

[0011] Furthermore, the widths of the first, second, and third flow channels are the same.

[0012] Furthermore, the flow channel is bent and meandering, with the first and second connecting bands located at the bends of the flow channel.

[0013] Furthermore, the plate body includes a first part, a second part, a third part, and a fourth part arranged sequentially along its length direction, and each of the first part, the second part, the third part, and the fourth part is provided with a flow channel groove.

[0014] Furthermore, the flow channel grooves in the first part are symmetrically arranged along the center line of the width of the first part, the flow channel grooves in the second part are symmetrically arranged along the center line of the width of the second part, the flow channel grooves in the third part are symmetrically arranged along the center line of the width of the third part, and the flow channel grooves in the fourth part are symmetrically arranged along the center line of the width of the fourth part.

[0015] Furthermore, the plate is a cathode plate, and the fuel cell bipolar plate also includes an anode plate and a membrane electrode assembly (MEA), with the MEA located between the cathode plate and the anode plate.

[0016] Furthermore, the flow channel is an air flow channel, and a water flow channel is also provided on the cathode plate. The flow channel is located on the first side of the cathode plate, the water flow channel is located on the second side of the cathode plate, and a hydrogen flow channel is provided on the first side of the anode plate.

[0017] The technical solution of this invention provides a flow channel groove on the plate, which has an inlet and an outlet. Between the inlet and outlet are multiple first flow channels and multiple second flow channels. The first flow channels are located upstream of the second flow channels in the flow direction of the flow channel, meaning the gas first passes through the first flow channel and then through the second flow channel. The number of first flow channels is greater than the number of second flow channels. Therefore, the gas flow velocity increases when the gas flows from the first flow channel to the second flow channel. This effectively enhances the drainage performance of the flow channel groove near the outlet, while also preventing the membrane electrode near the inlet from becoming too dry. The above technical solution balances drainage and moisture retention performance. Therefore, the technical solution of this application effectively solves the problem in related technologies where the membrane electrode at the inlet of the fuel cell bipolar plate is relatively dry, leading to low power generation efficiency of the fuel cell. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A front view schematic diagram of an embodiment of a fuel cell bipolar plate according to the present invention is shown;

[0020] Figure 2 It shows Figure 1 A partially enlarged schematic diagram of the bipolar plate of a fuel cell;

[0021] Figure 3 It shows Figure 2 A magnified view of part A of the bipolar plate of the fuel cell;

[0022] Figure 4 It shows Figure 2 A magnified view of part B of the bipolar plate of the fuel cell;

[0023] Figure 5 It shows Figure 1 A schematic diagram of the second and third flow channels of a fuel cell bipolar plate; and

[0024] Figure 6 It shows Figure 1 A three-dimensional structural diagram of the flow channel groove of the bipolar plate of a fuel cell.

[0025] The above figures include the following reference numerals:

[0026] 100, Plate; 110, First Part; 120, Second Part; 130, Third Part; 140, Fourth Part; 200, Flow Channel; 210, Inlet; 220, Outlet; 230, First Flow Channel; 240, Second Flow Channel; 241, First Flow Channel Section; 242, Second Flow Channel Section; 243, Third Flow Channel Section; 250, Third Flow Channel; 310, First Connecting Zone; 320, Second Connecting Zone. Detailed Implementation

[0027] 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 following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] In related technologies, the membrane electrode assembly (MEA) of a fuel cell requires a certain level of humidity to reduce its internal resistance and improve its performance. The flow channel also serves to humidify and retain moisture for the MEA; therefore, a certain level of humidity and liquid water must be maintained within the flow channel. Generally, a higher gas flow rate results in better drainage performance, but a higher gas flow rate is less conducive to humidifying and retaining moisture for the MEA. Consequently, the MEA upstream of the flow channel is typically drier.

[0031] In order to balance the drainage performance of the cathode plate and the moisture retention performance of the membrane electrode at the inlet, such as Figure 1 and Figure 2 As shown, in this embodiment, the fuel cell bipolar plate includes a plate body 100 and a flow channel 200. The flow channel 200 is disposed on the plate body 100 and includes an inlet 210 and an outlet 220. The flow channel 200 also includes a plurality of first flow channels 230 and a plurality of second flow channels 240 disposed between the inlet 210 and the outlet 220. The plurality of second flow channels 240 are located downstream of the plurality of first flow channels 230 in the flow direction of the flow channel 200, and the plurality of first flow channels 230 and the plurality of second flow channels 240 are interconnected. The number of first flow channels 230 is greater than the number of second flow channels 240.

[0032] In this embodiment, a flow channel 200 is provided on the plate 100. The flow channel 200 has an inlet 210 and an outlet 220. Between the inlet 210 and the outlet 220, there are multiple first flow channels 230 and multiple second flow channels 240. The first flow channels 230 are located upstream of the second flow channels 240 in the flow direction of the flow channel 200, meaning the gas first passes through the first flow channel 230 and then through the second flow channel 240. The number of first flow channels 230 is greater than the number of second flow channels 240. Therefore, when the gas flows from the first flow channel 230 to the second flow channel 240, the gas velocity increases. This effectively enhances the drainage performance of the flow channel near the outlet 220, while also preventing the membrane electrode near the inlet 210 from drying out. The above technical solution balances drainage and moisture retention. Therefore, the technical solution of this embodiment effectively solves the problem in related technologies where the membrane electrode at the inlet of the fuel cell bipolar plate is relatively dry, leading to low power generation efficiency of the fuel cell.

[0033] In order to increase the gas flow rate, such as Figure 2 and Figure 3 As shown, in this embodiment, the fuel cell bipolar plate includes a first connecting strip 310 located on the plate body 100. The first connecting strip 310 is located between a plurality of first flow channels 230 and a plurality of second flow channels 240. The first flow channels 230 are direct-flow channels, and the first connecting strip 310 is inclined relative to the first flow channels 230. The arrangement of the first connecting strip 310 allows gas flowing from the first flow channels 230 to the second flow channels 240 to accumulate at the first connecting strip 310 and enter the second flow channels 240, thus effectively accelerating the gas flow rate and improving the drainage capacity within the flow channel groove 200.

[0034] To further increase the gas flow rate in the flow channel 200, such as Figures 2 to 5 As shown, in this embodiment, the flow channel 200 further includes a plurality of third flow channels 250 disposed between the inlet 210 and the outlet 220. The number of third flow channels 250 is less than the number of second flow channels 240. Similarly, the number of third flow channels 250 is less than the number of first flow channels 230. The third flow channels 250 are located downstream of the second flow channels 240, and their placement further accelerates the gas flow rate in the flow channel 200. In this embodiment, the first flow channel 230 is connected to the inlet 210, the third flow channel 250 is connected to the outlet 220, and the second flow channel 240 is located between the first flow channel 230 and the third flow channel 250. The gas flow rate in the first flow channel is less than the gas flow rate in the second flow channel, and the gas flow rate in the second flow channel is less than the gas flow rate in the third flow channel. This ensures the drainage performance of the flow channel 200, while also preventing the gas flow rate at the inlet 210 from being too fast, which would cause the membrane electrode at the inlet 210 to be too dry.

[0035] like Figure 4 and Figure 5 As shown, in this embodiment, the fuel cell bipolar plate includes a second connecting strip 320 located on the plate body 100. The second connecting strip 320 is located between a plurality of second flow channels 240 and a plurality of third flow channels 250. The second connecting strip 320 is relative to the first flow channel 230. The second flow channel 240 includes a first flow channel segment 241, a second flow channel segment 242, and a third flow channel segment 243. The third flow channel segment 243 is disposed adjacent to the second connecting strip 320, and the first connecting strip 310 is disposed adjacent to the first flow channel segment 241. The second connecting strip 320 is located between the second flow channel 240 and the third flow channel 250. Gas in the second flow channel 240 flows into the second connecting strip 320 and then flows from the second connecting strip 320 into the third flow channel 250. In this embodiment, the first flow channel segment 241 is parallel to the third flow channel segment 243, and the second flow channel segment 242 is perpendicular to the first flow channel segment 241 and the third flow channel segment 243. The first connecting band 310 is located between the first flow channel 230 and the first flow channel segment 241, and the second connecting band 320 is located between the third flow channel 250 and the third flow channel segment 243.

[0036] like Figures 1 to 6 As shown, in this embodiment, the widths of the first flow channel 230, the second flow channel 240, and the third flow channel 250 are the same. The width of the flow channel groove 200 is equal at all points, which facilitates processing, effectively saves processing time, and improves production efficiency.

[0037] To make the arrangement of the flow channels more regular, such as Figure 1 and Figure 2 As shown, in this embodiment, the flow channel 200 is bent and meandering, with the first connecting band 310 and the second connecting band 320 located at the bends of the flow channel 200. Positioning the first connecting band 310 and the second connecting band 320 at the bends of the flow channel 200 facilitates the overall structural arrangement. Simultaneously, the gas flow velocity increases at the bends, and placing the first connecting band 310 and the second connecting band 320 at these bends helps buffer the flow velocity, preventing excessively high gas flow that could lead to membrane electrode drying and consequently affect fuel cell performance.

[0038] To improve the performance of bipolar plates, such as Figure 1As shown, in this embodiment, the plate 100 includes a first part 110, a second part 120, a third part 130, and a fourth part 140 arranged sequentially along its length. Each of the first part 110, the second part 120, the third part 130, and the fourth part 140 is provided with a flow channel groove 200. The plate 100 is divided into four parts, each with a flow channel groove 200. This ensures the exhaust performance of the bipolar plate and prevents the flow channel groove 200 from being too long, which would result in a slow gas flow rate inside the flow channel groove 200, making it difficult to achieve drainage.

[0039] like Figure 1 and Figure 2 As shown, in this embodiment, the flow channel grooves 200 in the first part 110 are symmetrically arranged along the center line of the width of the first part 110; the flow channel grooves 200 in the second part 120 are symmetrically arranged along the center line of the width of the second part 120; the flow channel grooves 200 in the third part 130 are symmetrically arranged along the center line of the width of the third part 130; and the flow channel grooves 200 in the fourth part 140 are symmetrically arranged along the center line of the width of the fourth part 140. This arrangement effectively increases the number of flow channel grooves, thereby improving the drainage performance of the bipolar plate. Furthermore, the symmetrical arrangement is easier to manufacture and implement.

[0040] It should be noted that, as Figure 1 and Figure 2 The center line of the width is the bisector of the side containing the inlet and outlet.

[0041] like Figure 1 As shown, in this embodiment, plate 100 is a cathode plate, and the fuel cell bipolar plate also includes an anode plate and a membrane electrode assembly (MEA), with the MEA located between the cathode plate and the anode plate. The anode plate, MEA, and cathode plate are combined into a set, and the fuel cell is composed of multiple sets stacked together.

[0042] like Figure 1 As shown, in this embodiment, the flow channel 200 is an air flow channel, and a water flow channel is also provided on the cathode plate. The flow channel 200 is located on the first side of the cathode plate, the water flow channel is located on the second side of the cathode plate, and a hydrogen flow channel is provided on the first side of the anode plate. The aforementioned water flow channel can effectively cool the cathode plate and prevent its temperature from becoming too high.

[0043] like Figures 1 to 5As shown, in this embodiment, the cathode plate includes four similar sections, which are flow field groups. Each flow field group includes multiple flow channel grooves. There are nine first flow channels 230, seven second flow channels 240, and five third flow channels 250. Gas enters from the first flow channel 230 into the second flow channel 240, where the cross-sectional area of ​​the flow channel 200 becomes 7 / 9 of its original size. The gas then flows from the second flow channel 240 into the third flow channel 250, where the cross-sectional area of ​​the flow channel 200 becomes 5 / 7 of its original size, and finally exits the flow channel 200 through the outlet 220. In summary, the cross-sectional area of ​​the gas flowing in the flow channel 200 becomes 5 / 9 of that at the inlet 210, and the gas flow rate is increased by approximately 100%. Therefore, the technical solution of this application accelerates the gas flow rate at the outlet 220, thus enhancing the downstream drainage capacity of the flow channel 200 while maintaining the humidification and moisture retention performance of the membrane electrode at the inlet 210, alleviating the problem of dryness of the membrane electrode at the inlet 210.

[0044] One side of the cathode plate is designed as an airflow channel, and the other side is designed as a cooling waterflow channel. One side of the anode plate is designed as a hydrogen flow channel, and the other side is a flat surface. The flat surface and the cooling water flow channel on the cathode plate cooperate to form a closed waterflow channel.

[0045] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0046] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0047] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fuel cell bipolar plate, characterized in that, include: Plate(100); A flow channel (200) is disposed on the plate (100). The flow channel (200) further includes an inlet (210) and an outlet (220). The flow channel (200) also includes a plurality of first flow channels (230) and a plurality of second flow channels (240) disposed between the inlet (210) and the outlet (220). The plurality of second flow channels (240) are located downstream of the plurality of first flow channels (230) in the flow direction of the flow channel (200), and the plurality of first flow channels (230) and the plurality of second flow channels (240) are interconnected. The number of the first flow channels (230) is greater than the number of the second flow channels (240); The fuel cell bipolar plate includes a first connecting strip (310) located on the plate body (100). The first connecting strip (310) is located between a plurality of first flow channels (230) and a plurality of second flow channels (240). The first flow channels (230) are direct flow channels. The first connecting strip (310) is inclined relative to the first flow channels (230). The plate body (100) is a cathode plate. The fuel cell bipolar plate also includes an anode plate and a membrane electrode assembly (MEA). The MEA is located between the cathode plate and the anode plate.

2. The fuel cell bipolar plate according to claim 1, characterized in that, The flow channel (200) also includes a plurality of third flow channels (250) disposed between the inlet (210) and the outlet (220), the number of the third flow channels (250) being less than the number of the second flow channels (240).

3. The fuel cell bipolar plate according to claim 2, characterized in that, The fuel cell bipolar plate includes a second connecting strip (320) located on the plate body (100). The second connecting strip (320) is located between a plurality of second flow channels (240) and a plurality of third flow channels (250). The second connecting strip (320) is relative to the first flow channel (230). The second flow channel (240) includes a first flow channel segment (241), a second flow channel segment (242), and a third flow channel segment (243). The third flow channel segment (243) is arranged adjacent to the second connecting strip (320), and the first connecting strip (310) is arranged adjacent to the first flow channel segment (241).

4. The fuel cell bipolar plate according to claim 2, characterized in that, The first flow channel (230), the second flow channel (240), and the third flow channel (250) have the same width.

5. The fuel cell bipolar plate according to claim 3, characterized in that, The flow channel (200) is bent and meandering, and the first connecting band (310) and the second connecting band (320) are located at the bends of the flow channel (200).

6. The fuel cell bipolar plate according to claim 1, characterized in that, The plate (100) includes a first part (110), a second part (120), a third part (130) and a fourth part (140) arranged sequentially along its length. The first part (110), the second part (120), the third part (130) and the fourth part (140) are all provided with the flow channel groove (200).

7. The fuel cell bipolar plate according to claim 6, characterized in that, The flow channel grooves (200) in the first part (110) are symmetrically arranged along the center line of the width of the first part (110), the flow channel grooves (200) in the second part (120) are symmetrically arranged along the center line of the width of the second part (120), the flow channel grooves (200) in the third part (130) are symmetrically arranged along the center line of the width of the third part (130), and the flow channel grooves (200) in the fourth part (140) are symmetrically arranged along the center line of the width of the fourth part (140).

8. The fuel cell bipolar plate according to claim 1, characterized in that, The flow channel (200) is an air flow channel, and a water flow channel is also provided on the cathode plate. The flow channel (200) is located on the first side of the cathode plate, the water flow channel is located on the second side of the cathode plate, and a hydrogen flow channel is provided on the first side of the anode plate.

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