Throttling flow channel design method and bipolar plate flow channel

Abstract

The invention provides a throttling flow channel design method and a bipolar plate flow channel. The throttling flow channel design method comprises the steps that the size of a main flow channel and the number x of throttling structures arranged on the main flow channel are obtained; and the throttling sectional area Si of the throttling structures is selected according to the size of the main flow channel and the number x of the throttling structures, so that the flow channel performance index obtained according to the throttling sectional area Si is within the preset flow channel performance index range. By finely adjusting the sizes and structures of the main flow channel and the throttling structure, the mass transfer and drainage performances of the fuel cell are obviously optimized, and the efficiency and stability of the fuel cell are effectively improved. The method not only considers the performance index of the flow channel, but also considers the limitation of the processing technology, ensures the feasibility and economy of the design, provides powerful support for the development of the fuel cell technology, and solves the problem that the throttling flow channel in the bipolar plate of the fuel cell in the prior art cannot meet the technological requirements and has higher performance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of flow channel design, and in particular to a throttling flow channel design method and a bipolar plate flow channel. Background Art

[0002] The electrocatalytically coupled proton exchange membrane fuel cell (PEMFC) is an efficient energy conversion device that uses hydrogen as fuel to carry out chemical reactions and directly convert chemical energy into electrical energy. It has the advantages of high energy conversion efficiency, environmental friendliness, and a wide range of fuel applications.

[0003] The bipolar plate in the fuel cell is a structural component that performs the functions of conduction, heat dissipation, support, sealing, and mechanical fixation. There are flow channels on the bipolar plate, and the fuel (or combustion aid) and oxygen enter the fuel cell through the flow channels respectively, and react chemically with the electrocatalyst layer to generate current and water vapor. Therefore, the structural design of the flow channel has a significant impact on the performance of the fuel cell.

[0004] An important goal of flow channel structure design is to enhance mass transfer efficiency, improve drainage capacity, and control the flow resistance of the flow channel within a reasonable range. Although the traditional straight flow channel has a small resistance, its drainage and mass transfer capacity under the ridge is relatively weak. The throttling flow channel increases the local flow channel pressure drop by reducing the local flow cross-section, enhances the mass transfer and drainage capacity under the ridge, and thus effectively improves the overall performance of the fuel cell. However, in order to achieve this expected effect, it is often necessary to design extremely small local flow channel dimensions, which poses a great challenge in the processing technology. Faced with the problem of how to optimize the throttling flow channel design within the limitations of the processing technology, there is currently a lack of effective methods. Summary of the invention

[0005] The main purpose of the present invention is to provide a throttling flow channel design method and a bipolar plate flow channel to solve the problem that the throttling flow channel in the bipolar plate of a fuel cell in the prior art cannot simultaneously meet the process requirements and have higher performance.

[0006] In order to achieve the above object, according to one aspect of the present invention, a throttling flow channel design method is provided, comprising: obtaining a main flow channel size of a main flow channel and a number x of throttling structures arranged on the main flow channel; selecting a throttling cross-sectional area S of the throttling structure according to the main flow channel size and the number x of throttling structures i , so that according to the throttling cross-sectional area S i The obtained flow channel performance index is within the range of the predetermined flow channel performance index.

[0007] Furthermore, the throttling channel design method further includes: selecting a first throttling cross-sectional area S according to the size of the main channel and the number of throttling structures x 1 ; According to the first throttling cross-sectional area S 1Obtain a first flow channel performance index; if the first flow channel performance index is within the range of a predetermined flow channel performance index, determine a first throttling cross-sectional area S 1 is the minimum throttling cross-sectional area S; if the first flow channel performance index is outside the range of the predetermined flow channel performance index, the Nth throttling cross-sectional area S of the throttling structure is selected in sequence n , until the Nth throttling cross-sectional area S n If the Nth flow channel performance index obtained is within the range of the predetermined flow channel performance index, the Nth throttling cross-sectional area S is determined. n is the minimum throttling cross-sectional area S.

[0008] Further, obtaining the flow channel performance index includes: obtaining the flow channel flow resistance P i , sub-ridge convection flow Q i ; Among them, the flow resistance P i and subridge convection Q i and throttling cross-sectional area S i There is a linear negative correlation.

[0009] Further, obtaining the flow channel performance index includes: obtaining the oxygen concentration decay rate δ i ; Among them, the oxygen concentration decay rate δ i for is the oxygen concentration in the flow channel, is the minimum oxygen concentration; oxygen concentration decay rate δ i and throttling cross-sectional area S i There is a linear positive correlation.

[0010] Further, obtaining the main channel size includes: obtaining the main channel bottom width L 1 , Main channel depth L 2 and main channel membrane extraction angle α.

[0011] Furthermore, the throttling flow channel design method also includes: selecting a throttling size of the throttling structure according to the throttling minimum cross-sectional area S so that the throttling size is within a processable range.

[0012] Furthermore, the throttling flow channel design method also includes: selecting a first throttling size of the throttling structure according to the minimum throttling cross-sectional area S; if the first throttling size is within the processable range, determining the first throttling size as the processing throttling size; if the first throttling size is outside the processable range, selecting the Nth throttling size of the throttling structure in sequence until the Nth throttling size is within the processable range, and then determining the Nth throttling size as the processing throttling size.

[0013] Furthermore, the throttling flow channel design method further includes: selecting the throttling structure bottom width w, the throttling structure depth h and the throttling structure film drawing angle θ according to the throttling minimum cross-sectional area S; wherein the throttling minimum cross-sectional area S is S=wh+h 2tanθ; if the throttling structure bottom width w, throttling structure depth h and throttling structure film extraction angle θ satisfy w+2h tanθ<w ch_top and w>w min , then the throttling size is within the processable range; where w ch_top is the top width of the main channel, w min It is the minimum size allowed by machining accuracy.

[0014] According to another aspect of the present invention, a bipolar plate flow channel is provided, which is applicable to the above-mentioned throttling flow channel design method, and the bipolar plate flow channel comprises: a main flow channel; and a throttling structure arranged on the main flow channel.

[0015] Further, there are multiple throttling structures, which are spaced apart along the extension direction of the main flow channel; and / or there are multiple main flow channels, which are spaced apart along a direction perpendicular to the extension direction of the main flow channel.

[0016] Applying the technical solution of the present invention, the present invention provides a throttling flow channel design method, which includes: obtaining the main flow channel size of the main flow channel and the number x of throttling structures set on the main flow channel; selecting the throttling cross-sectional area S of the throttling structure according to the main flow channel size and the number x of throttling structures i , so that according to the throttling cross-sectional area S i The obtained flow channel performance index is within the range of the predetermined flow channel performance index. By finely adjusting the size and structure of the main flow channel and the throttling structure, the mass transfer and drainage performance of the fuel cell are significantly optimized, and the efficiency and stability of the fuel cell are effectively improved. This method not only takes into account the performance index of the flow channel, but also takes into account the limitations of the processing technology, ensuring the feasibility and economy of the design, and providing strong support for the development of fuel cell technology. The effectiveness of the design is verified by simulation calculation, and the accuracy of the flow channel design is further guaranteed, so that the fuel cell can show better performance in practical applications, opening up a new path for the promotion and application of clean energy, and solving the problem that the throttling flow channel in the fuel cell bipolar plate in the prior art cannot simultaneously meet the process requirements and have high performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic flow chart showing an embodiment of a throttling flow channel design method according to the present invention is shown;

[0019] Figure 2A linear correlation diagram between the flow resistance P of the flow channel, the convection flow Q under the ridge, the oxygen concentration decay rate δ and the throttling minimum cross-sectional area S according to the throttling flow channel design method of the present invention is shown;

[0020] Figure 3 A schematic structural diagram of a throttling channel of a bipolar plate channel according to the present invention from a first perspective is shown;

[0021] Figure 4 A second perspective structural schematic diagram of a throttling flow channel of a bipolar plate flow channel according to the present invention is shown;

[0022] Figure 5 A third perspective structural schematic diagram of a throttling flow channel of a bipolar plate flow channel according to the present invention is shown;

[0023] Figure 6 A schematic diagram showing the minimum cross-sectional characteristic dimensions of a throttling structure according to a throttling flow channel design method of the present invention is shown;

[0024] Figure 7 A schematic diagram showing the arrangement of the main flow channel and the throttling structure of the bipolar plate flow channel according to the present invention is shown;

[0025] Figure 8 A schematic diagram showing simulation calculation results of flow resistance P of a flow channel according to an embodiment of the throttling flow channel design method of the present invention is shown;

[0026] Fig. 9 A schematic diagram showing simulation calculation results of flow rate Q under a ridge according to an embodiment of a throttling flow channel design method of the present invention is shown;

[0027] Fig.10 A schematic diagram showing simulation calculation results of the oxygen concentration decay rate δ according to an embodiment of the throttling flow channel design method of the present invention is shown.

[0028] The above drawings include the following reference numerals:

[0029] 1. Main flow channel; 2. Throttling structure. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] Please refer to Figures 1 to 10 The present invention provides a throttling flow channel design method, comprising: obtaining a main flow channel size of a main flow channel and a number x of throttling structures arranged on the main flow channel; selecting a throttling cross-sectional area S of the throttling flow channel according to the main flow channel size and the number x of throttling structures i , so that according to the throttling cross-sectional area S iThe obtained flow channel performance index is within the range of the predetermined flow channel performance index.

[0032] The present invention provides a throttling flow channel design method, which includes: obtaining the main flow channel size of the main flow channel and the number x of throttling structures arranged on the main flow channel; selecting the throttling cross-sectional area S of the throttling structure according to the main flow channel size and the number x of throttling structures; i , so that according to the throttling cross-sectional area S i The obtained flow channel performance index is within the range of the predetermined flow channel performance index. By finely adjusting the size and structure of the main flow channel and the throttling structure, the mass transfer and drainage performance of the fuel cell are significantly optimized, and the efficiency and stability of the fuel cell are effectively improved. This method not only takes into account the performance index of the flow channel, but also takes into account the limitations of the processing technology, ensuring the feasibility and economy of the design, and providing strong support for the development of fuel cell technology. The effectiveness of the design is verified by simulation calculation, and the accuracy of the flow channel design is further guaranteed, so that the fuel cell can show better performance in practical applications, opening up a new path for the promotion and application of clean energy, and solving the problem that the throttling flow channel in the fuel cell bipolar plate in the prior art cannot simultaneously meet the process requirements and have high performance.

[0033] Specifically, the throttling channel design method further includes: selecting a first throttling cross-sectional area S according to the size of the main channel and the number of throttling structures x 1 ; According to the first throttling cross-sectional area S 1 Obtain a first flow channel performance index; if the first flow channel performance index is within the range of a predetermined flow channel performance index, determine a first throttling cross-sectional area S 1 is the minimum throttling cross-sectional area S; if the first flow channel performance index is outside the range of the predetermined flow channel performance index, the Nth throttling cross-sectional area S of the throttling structure is selected in sequence n , until the Nth throttling cross-sectional area S n If the Nth flow channel performance index obtained is within the range of the predetermined flow channel performance index, the Nth throttling cross-sectional area S is determined. n is the minimum throttling cross-sectional area S.

[0034] Further, obtaining the flow channel performance index includes: obtaining the flow channel flow resistance P i , sub-ridge convection flow Q i ; Among them, the flow resistance P i and subridge convection Q i and throttling cross-sectional area S i There is a linear negative correlation.

[0035] Similarly, obtaining flow channel performance indicators includes: obtaining the oxygen concentration decay rate δ i ; Among them, the oxygen concentration decay rate δ i for is the oxygen concentration in the flow channel, is the minimum oxygen concentration; oxygen concentration decay rate δ i and throttling cross-sectional area S i There is a linear positive correlation.

[0036] Optionally, obtaining the main channel size includes: obtaining the main channel bottom width L 1 , Main channel depth L 2 and main channel membrane extraction angle α.

[0037] Furthermore, the throttling channel design method also includes: selecting a throttling size of the throttling channel according to the throttling minimum cross-sectional area S so that the throttling size is within a processable range.

[0038] Specifically, the throttling channel design method also includes: selecting a first throttling size of the throttling structure according to the minimum throttling cross-sectional area S; if the first throttling size is within the processable range of the main channel size, determining the first throttling size as the processing throttling size; if the first throttling size is outside the processable range of the main channel size, selecting the Nth throttling size of the throttling structure in sequence until the Nth throttling size is within the processable range, and then determining the Nth throttling size as the processing throttling size.

[0039] Furthermore, the throttling flow channel design method further includes: selecting the throttling structure bottom width w, the throttling structure depth h and the throttling structure film drawing angle θ according to the throttling minimum cross-sectional area S; wherein the throttling minimum cross-sectional area S is S=wh+h 2 tanθ; if the throttling structure bottom width w, throttling structure depth h and throttling structure film extraction angle θ satisfy w+2h tanθ<w ch_top and w>w min , then the throttling structure size is within the processable range; where w ch_top is the top width of the main channel, w min It is the minimum size allowed by machining accuracy.

[0040] The present invention also provides a bipolar plate flow channel, which is suitable for the above-mentioned throttling flow channel design method, such as Figures 3 to 5 As shown, the bipolar plate flow channel includes: a main flow channel 1; and a throttling structure 2, which is arranged on the main flow channel 1.

[0041] Specifically, Figure 7 As shown, there are multiple throttling structures 2, and the multiple throttling structures 2 are arranged at intervals along the extension direction of the main flow channel 1; there are multiple main flow channels 1, and the multiple main flow channels 1 are arranged at intervals along the direction perpendicular to the extension direction of the main flow channel 1.

[0042] In a specific embodiment, the specific implementation steps of the throttling flow channel design method provided in this embodiment are:

[0043] Step 1: Based on the structural parameters of the bipolar plate flow channel, determine that the main flow channel 1 is a straight flow channel and the bottom width of the main flow channel is L1 =0.46mm, main channel depth L 2 =0.35mm, main channel draft angle α=15°, the number of throttling structures set on a single main channel x=7, and the throttling length is 4mm;

[0044] Step 2: According to the design requirements, the flow resistance P of the flow channel should be within the range of 10-15 kPa, and the flow rate Q under the ridge should be greater than 3×10 -6 kg / s, the average oxygen concentration decay rate δ should be less than 13%. Select the minimum cross-sectional area of ​​the throttling flow region S = 0.0476mm 2 ,After simulation calculation, the flow resistance P of the flow channel, the flow rate Q under the ridge, and the oxygen concentration decay rate δ are all within the required range;

[0045] Step 3: According to the processing boundary and flow channel size restrictions, w min =0.2mm, w ch_top =0.65mm, select the throttling size, the bottom width of the throttling structure w=0.2mm, the depth of the throttling structure h=0.138mm, the throttling structure film pulling angle θ=50°, and substitute the inequality w+2htanθ<w ch_top and w>w min Verify in, the inequality holds;

[0046] Step 4: Model the throttling channel based on the main channel size and throttling size calculated above. The specific structure is shown in Figure 6 ;

[0047] Step 5: Use ANSYS Fluent software to simulate the flow and mass transfer of the throttling channel. The results are as follows: Figures 8 to 10 The flow resistance P of the flow channel is 12.85 kPa, and the convection flow Q under the ridge is 3.39×10 -6 kg / s and the average oxygen concentration decay rate δ is 12.17%, both of which meet the design requirements.

[0048] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0049] The present invention provides a throttling flow channel design method, which includes: obtaining the main flow channel size of the main flow channel and the number x of throttling structures arranged on the main flow channel; selecting the throttling cross-sectional area S of the throttling structure according to the main flow channel size and the number x of throttling structures; i , so that according to the throttling cross-sectional area S iThe obtained flow channel performance index is within the range of the predetermined flow channel performance index. By finely adjusting the size and structure of the main flow channel and the throttling structure, the mass transfer and drainage performance of the fuel cell are significantly optimized, and the efficiency and stability of the fuel cell are effectively improved. This method not only takes into account the performance index of the flow channel, but also takes into account the limitations of the processing technology, ensuring the feasibility and economy of the design, and providing strong support for the development of fuel cell technology. The effectiveness of the design is verified by simulation calculation, and the accuracy of the flow channel design is further guaranteed, so that the fuel cell can show better performance in practical applications, opening up a new path for the promotion and application of clean energy, and solving the problem that the throttling flow channel in the fuel cell bipolar plate in the prior art cannot simultaneously meet the process requirements and have high performance.

[0050] The throttling flow channel design method proposed in the present invention can flexibly change the throttling characteristic size based on the principle that the minimum cross-sectional area of ​​the throttling flow region remains unchanged, and ensures that the throttling flow channel has high performance while complying with the process requirements. The design method has great compatibility with processing and production, and provides a solution to the problem that high-performance throttling flow channels cannot be processed from the design end.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A throttling channel design method, characterized in that: include: Obtaining the main channel size of the main channel and the number x of throttling structures set on the main channel; The throttling cross-sectional area S of the throttling structure is selected according to the main flow channel size and the number x of the throttling structures. i , so that according to the throttling cross-sectional area S i The obtained flow channel performance index is within the range of the predetermined flow channel performance index.

2. The throttling channel design method according to claim 1, characterized in that: The throttling flow channel design method also includes: Selecting a first throttling cross-sectional area S1 according to the main flow channel size and the number x of throttling structures; Obtaining a first flow channel performance index according to the first throttling cross-sectional area S1; If the first flow channel performance index is within the range of the predetermined flow channel performance index, the first throttling cross-sectional area S1 is determined to be the minimum throttling cross-sectional area S; If the first flow channel performance index is outside the range of the predetermined flow channel performance index, the Nth throttling cross-sectional area S of the throttling structure is selected in sequence. n , until according to the Nth throttling cross-sectional area S n The obtained Nth flow channel performance index is within the range of the predetermined flow channel performance index, then the Nth throttling cross-sectional area S is determined. n is the minimum throttling cross-sectional area S.

3. The throttling channel design method according to claim 1, characterized in that: The flow channel performance indicators include: Get the flow resistance P of the flow channel i , sub-ridge convection flow Q i ; Wherein, the flow channel resistance P i and the ridge convection flow Q i With the throttling cross-sectional area S i There is a linear negative correlation.

4. The throttling channel design method according to claim 1, characterized in that: The flow channel performance indicators include: Get the oxygen concentration decay rate δ i ; Among them, the oxygen concentration decay rate δ i for is the oxygen concentration in the flow channel, is the minimum oxygen concentration; the oxygen concentration decay rate δ i With the throttling cross-sectional area S i There is a linear positive correlation.

5. The throttling channel design method according to claim 1, characterized in that: Obtaining the main flow channel size includes: Obtain the main channel bottom width L1, the main channel depth L2 and the main channel film stripping angle α.

6. The throttling channel design method according to claim 2, characterized in that: The throttling flow channel design method also includes: The throttling size of the throttling structure is selected according to the throttling minimum cross-sectional area S so that the throttling size is within a processable range.

7. The throttling channel design method according to claim 6, characterized in that: The throttling flow channel design method also includes: Selecting a first throttling size of the throttling structure according to the throttling minimum cross-sectional area S; If the first throttling size is within the processable range, determining the first throttling size as the process throttling flow channel size; If the first throttling size is outside the processable range, the Nth throttling size of the throttling structure is selected in sequence until the Nth throttling size is within the processable range, and the Nth throttling size is determined as the processing throttling size.

8. The throttling channel design method according to claim 6, characterized in that: The throttling flow channel design method also includes: According to the minimum throttling cross-sectional area S, the bottom width w of the throttling structure, the depth h of the throttling structure and the film drawing angle θ of the throttling structure are selected; wherein the minimum throttling cross-sectional area S is S=wh+h 2 tanθ; If the bottom width w of the throttling structure, the depth h of the throttling structure and the film drawing angle θ of the throttling structure satisfy w+2htanθ<w ch_top and w>w min , then the throttling size is within the processable range of the main channel size; where w ch_top is the top width of the main channel, w min It is the minimum size allowed by machining accuracy.

9. A bipolar plate flow channel, characterized in that: The throttling channel design method applicable to any one of claims 1 to 8, wherein the bipolar plate channel comprises: Main channel (1); The throttling structure (2) is arranged on the main flow channel (1).

10. The bipolar plate flow channel according to claim 9, characterized in that: There are a plurality of throttling structures (2), and the plurality of throttling structures (2) are arranged at intervals along the extension direction of the main flow channel (1); and / or There are a plurality of main flow channels (1), and the plurality of main flow channels (1) are arranged at intervals along a direction perpendicular to the direction in which the main flow channels (1) extend.

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