Visual simulation method for evaluating flow distribution consistency of battery bipolar plate

Abstract

The application relates to the field of fuel cells, in particular to a visual simulation method for evaluating the flow distribution consistency of a fuel cell bipolar plate, which comprises the following steps: S1, importing a bipolar plate model into simulation software, and extracting a finite element model of a complete flow channel; S2, separating the whole flow channel from the middle, and generating an interface between two flow channel bodies; S3, carrying out meshing on the finite element model; S4, separating the interface into actual numbers of single sub-flow channel interfaces; S5, setting boundary conditions, and setting flow monitoring surfaces on all sub-flow channel interfaces; S6, submitting a deviation rate calculation, and setting an experienced deviation rate parameter value; S7, finding the interface serial number exceeding the set deviation rate parameter value, and correspondingly finding a flow channel, and adjusting the structure of the flow channel. The application provides a specific quantitative and visual method for the flow distribution consistency design of the bipolar plate, and sample processing and testing are not needed.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a visual simulation method for evaluating the consistency of bipolar plate flow distribution in a fuel cell. Background Technology

[0002] Bipolar plates are crucial components of fuel cells, including the cathode side, anode side, and cooling path. They primarily function to separate fuel from oxidant, collect and conduct current, and supply hydrogen, oxygen, and coolant. The structural design of the bipolar plate flow channels determines the uniformity of gas and coolant distribution, thereby influencing reaction efficiency.

[0003] Existing bipolar plate structures are generally divided into a distribution zone and a reaction zone. The structure within the reaction zone is mostly a long and dense serpentine flow channel or a direct-flow channel. Gas enters the reaction zone from the distribution zone, but the designed structure cannot guarantee the uniformity of gas flow distribution in each channel. It is necessary to manufacture prototypes and analyze the uniformity of gas flow distribution through performance tests, which is time-consuming, costly, and not intuitive. Summary of the Invention

[0004] The purpose of this invention is to address the problems in the prior art where it is necessary to manufacture samples and analyze the uniformity of gas flow distribution through performance tests, which is time-consuming, costly, and not intuitive. The invention proposes a visual simulation method for evaluating the consistency of gas flow distribution in battery bipolar plates.

[0005] The technical solution of this invention: A visual simulation method for evaluating the consistency of flow distribution in battery bipolar plates, comprising the following steps:

[0006] S1. Import the bipolar plate 3D model into the preprocessing module of the simulation software, and then use the flow channel extraction function to close the inlet, outlet and intermediate flow channel of the model, thereby extracting the finite element model of the complete flow channel, and naming the boundary surface at the same time.

[0007] S2. The overall flow channel is split in the middle to form inlet and outlet flow channel body one and flow channel body two. An interface surface is generated between the two flow channel bodies so that the flow rate value of the middle section can be extracted.

[0008] S3. Mesh the processed finite element model;

[0009] S4. In the simulation software, the interface is separated into the actual number of individual interfaces for each sub-channel, and each sub-channel is assigned a number, 1, 2, 3...n;

[0010] S5. Set boundary conditions in the simulation software, set flow monitoring surfaces at the interfaces of all sub-channels, and generate record files.

[0011] S6. Submit the deviation rate calculation. When the residual value reaches the set value, it means that the calculation has been completed. Set a deviation rate parameter value based on experience.

[0012] S7. Find the interface number that exceeds the set deviation rate parameter value, and find the corresponding flow channel in the simulation software. After locking the flow channel, make corresponding structural adjustments to this flow channel. After repeated structural adjustments and calculation iterations, finally achieve a deviation rate of zero for all sub-flow channels, with the upper and lower fluctuation ranges all within the absolute value of the set deviation rate parameter value.

[0013] Preferably, in step S3, mesh generation includes the following steps: S31, selecting a suitable mesh type; S32, setting mesh parameters; S33, automatic mesh generation using the automatic mesh generation tool of the simulation software; S34, manual mesh adjustment; S35, mesh quality check using the mesh quality tool of the simulation software to evaluate the quality of the generated mesh; S36, mesh independence test to confirm whether the mesh generation is sufficiently fine to capture the flow characteristics of the fluid.

[0014] Preferably, in S31, a suitable mesh type is selected based on the geometric characteristics of the bipolar plate flow channel and the simulation requirements; a tetrahedral mesh is used.

[0015] Preferably, in step S6, the flow rate values ​​Q′ at all sub-channel interfaces in the record file, where Q′ is the actual flow rate of the sub-channel, are copied to an Excel spreadsheet and analyzed according to the uniformity formula. The deviation rate of each sub-channel is calculated based on the theoretical design flow rate of the sub-channel.

[0016] Preferably, in S7, the flow channel adjustment includes the following steps: S71, analyzing the flow channel characteristics; S72, adjusting the flow channel structure, including: changing the flow channel cross-sectional shape, adjusting the flow channel size, optimizing the flow channel bending angle, and removing or adding obstacles in the flow channel; S73, re-meshing the adjusted flow channel to ensure that the mesh quality meets the simulation requirements; S74, setting new boundary conditions and monitoring points.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: it provides a specific quantitative and visual method for the design of bipolar plate flow distribution consistency; it can quickly measure the consistency of bipolar plate flow distribution without the need for sample processing and testing, and can quickly identify the flow channels where the consistency deviation occurs, providing a basis for specific design improvement. After repeated adjustments, the consistency can be adjusted to the design target value. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0019] Figure 2 A flowchart for mesh generation;

[0020] Figure 3 This is a flowchart for flow channel adjustment. Detailed Implementation

[0021] Example 1

[0022] like Figure 1 As shown, the present invention proposes a visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery, comprising the following steps:

[0023] S1. Import the bipolar plate 3D model into the preprocessing module of the simulation software, and then use the flow channel extraction function to close the inlet, outlet and intermediate flow channel of the model, thereby extracting the finite element model of the complete flow channel, and naming the boundary surface at the same time.

[0024] S2. The overall flow channel is split in the middle to form inlet and outlet flow channel body one and flow channel body two. An interface is generated between the two flow channel bodies so that the flow rate value of the middle section can be extracted. The interface is for information transmission and data exchange between different flow channel bodies during the simulation process.

[0025] S3. Mesh the processed finite element model. Mesh generation is to simplify the complex flow channel model and facilitate numerical calculation.

[0026] S4. In the simulation software, the interface is separated into the actual number of individual interfaces for each sub-channel, and each sub-channel is assigned a number, 1, 2, 3...n. This allows the flow rate value of each sub-channel to be extracted separately, which is convenient for subsequent processing.

[0027] S5. Set boundary conditions in the simulation software, including the selection of the physical model, the parameters of the flowing medium, the flow rate, pressure, temperature and other parameters of the inlet and outlet boundary surfaces, and set the flow monitoring surface for all sub-channel interfaces, and generate a .out log file.

[0028] S6. Submit deviation rate calculation. When the residual value reaches the set value, the calculation is complete. Copy the flow rate values ​​Q′ (the actual flow rate of the sub-channel) of all sub-channel interfaces from the record file to an Excel spreadsheet. Then, based on the uniformity formula... To calculate the design flow rate of each sub-channel in theory, the deviation rate of each sub-channel is calculated, and a deviation rate parameter value is set based on experience, for example, controlled at around 10%.

[0029] S7. Based on the statistical results in the Excel spreadsheet, the interface number exceeding the set deviation rate parameter value (i.e., the interface number exceeding 10%) can be found. The corresponding flow channel can then be located in the simulation software. After locking the flow channel, appropriate structural adjustments can be made. For example, if the deviation rate is in the range of 0-10%, it indicates that the flow rate of this flow channel is too high. Methods such as reducing the flow area can be used to increase flow resistance, thereby reducing the flow rate of this flow channel. If the deviation rate is in the range of -10%-0, it indicates that the flow rate of this flow channel is too low. Methods such as increasing the flow area can be used to reduce flow resistance, thereby increasing the flow rate of this flow channel. After repeated structural adjustments and calculation iterations, the deviation rate of all sub-flow channels must be zero, with fluctuations within the absolute value of the set deviation rate parameter value (i.e., within -10%-10%). Only then can the set flow distribution consistency requirements be met, and only then can the final consistent pattern structure be processed.

[0030] Example 2

[0031] like Figure 2 As shown, this invention proposes a visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery. Compared with Embodiment 1, this embodiment details the mesh generation steps in S3.

[0032] Specifically, this includes: S31, selecting a suitable mesh type. Based on the geometric characteristics of the bipolar plate flow channel and simulation requirements, a suitable mesh type is selected. Common mesh types include tetrahedral meshes, hexahedral meshes, triangular meshes, and rectangular meshes. Tetrahedral meshes have good adaptability but require high quality control; hexahedral meshes are commonly used in dynamic analysis, but the generation process is complex; triangular and rectangular meshes are used in specific situations, such as structural analysis, and are selected according to actual needs. In this invention, tetrahedral meshes are used; S32, setting mesh parameters. Mesh parameters are set in the simulation software, including mesh size, mesh density, and mesh type. The mesh size needs to be determined based on the size and characteristics of the flow channel, while the mesh density needs to be set according to the complexity of the fluid flow and the required computational accuracy. S33. Automatic mesh generation: Use the automatic mesh generation tool in the simulation software. This step typically includes the following operations: First, define the mesh generation region, defining which areas on the model need meshing and which do not. Then, select a mesh generation algorithm, choosing a suitable algorithm based on the characteristics of the flow channel, such as structured mesh generation or unstructured mesh generation. Next, adjust the mesh generation parameters as needed, such as maximum and minimum mesh size, mesh growth rate, and mesh smoothness. S34. Manual mesh adjustment: This mainly includes deleting overlapping or isolated mesh cells, eliminating sharp angles and folds in the mesh, and increasing or decreasing the number of mesh cells to adapt to specific analysis needs or improve the mesh quality in local areas. S35. Mesh quality check: Use the mesh quality tool in the simulation software to evaluate the quality of the generated mesh. The check includes mesh uniformity, orthogonality, and the ratio of maximum to minimum size. Based on the inspection results, it may be necessary to repeat the above steps of manually adjusting the mesh; S36, mesh independence test, to confirm whether the mesh is fine enough to capture the flow characteristics of the fluid, which is usually done by changing the mesh size and observing the changes in the calculation results. If the changes in the results are small, it indicates that the mesh is independent.

[0033] Example 3

[0034] like Figure 3 As shown, this invention proposes a visual simulation method for evaluating the consistency of bipolar plate flow distribution in a battery. Compared to Embodiment 1, this embodiment details the steps of flow channel adjustment in S7.

[0035] Specifically, this includes: S71, analyzing flow channel characteristics, including the cross-sectional shape, size, length, and velocity of the fluid within the channel, to determine specific factors affecting flow distribution, such as the cross-sectional area, curvature, and obstructions; S72, adjusting the flow channel structure, including: changing the cross-sectional shape (e.g., from circular to rectangular) or adjusting the wall thickness; adjusting the channel dimensions (increasing or decreasing the width or height to alter the velocity distribution); optimizing the curvature angle to reduce turbulence and eddies; and removing or adding obstructions, such as baffles or regulators, to change the fluid flow path; S73, re-meshing the adjusted flow channel to ensure the mesh quality meets simulation requirements, potentially requiring more detailed meshing, especially in the adjusted region, to ensure accurate capture of flow details; and S74, setting new boundary conditions and monitoring points, resetting flow monitoring points at the channel interfaces for subsequent recalculation and analysis.

[0036] In summary, this invention provides a specific quantitative and visual method for the design of bipolar plate flow distribution consistency. It eliminates the need for sample processing and testing, and can quickly measure the consistency of bipolar plate flow distribution. Furthermore, it can quickly identify flow channels where consistency deviations occur, providing a basis for specific design improvements. Through repeated adjustments, the consistency can be adjusted to the design target value.

[0037] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A visual simulation method for evaluating the consistency of flow distribution in a battery bipolar plate, characterized in that, Includes the following steps: S1. Import the bipolar plate 3D model into the preprocessing module of the simulation software, and then use the flow channel extraction function to close the inlet, outlet and intermediate flow channel of the model, thereby extracting the finite element model of the complete flow channel, and naming the boundary surface at the same time. S2. The overall flow channel is split in the middle to form inlet and outlet flow channel body one and flow channel body two. An interface surface is generated between the two flow channel bodies so that the flow rate value of the middle section can be extracted. S3. Mesh the processed finite element model; S4. In the simulation software, the interface is separated into the actual number of individual interfaces for each sub-channel, and each sub-channel is assigned a number, 1, 2, 3...n; S5. Set boundary conditions in the simulation software, set flow monitoring surfaces at the interfaces of all sub-channels, and generate record files. S6. Submit the deviation rate calculation. When the residual value reaches the set value, it means that the calculation has been completed. Set a deviation rate parameter value based on experience. S7. Find the interface number that exceeds the set deviation rate parameter value, and find the corresponding flow channel in the simulation software. After locking the flow channel, make corresponding structural adjustments to this flow channel. After repeated structural adjustments and calculation iterations, finally achieve a deviation rate of zero for all sub-flow channels, with the upper and lower fluctuation ranges all within the absolute value of the set deviation rate parameter value.

2. The visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery according to claim 1, characterized in that, In S3, mesh generation includes the following steps: S31, select a suitable mesh type; S32, set mesh parameters; S33, automatic mesh generation, using the simulation software's automatic mesh generation tool; S34, manual mesh adjustment; S35, mesh quality check, using the simulation software's mesh quality tool to evaluate the quality of the generated mesh; S36, mesh independence test, to confirm whether the mesh generation is fine enough to capture the fluid flow characteristics.

3. The visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery according to claim 2, characterized in that, In S31, a suitable mesh type is selected based on the geometric characteristics of the bipolar plate flow channel and the simulation requirements. Here, a tetrahedral mesh is selected.

4. The visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery according to claim 1, characterized in that, In S6, the flow rate values ​​Q′ at all sub-channel interfaces in the record file, where Q′ is the actual flow rate of the sub-channel, are copied to an Excel spreadsheet and then processed according to the uniformity formula. The deviation rate of each sub-channel is calculated based on the theoretical design flow rate of the sub-channel.

5. The visualization simulation method for evaluating the consistency of bipolar plate flow distribution in a battery according to claim 1, characterized in that, In S7, the flow channel adjustment includes the following steps: S71, analyze the flow channel characteristics; S72, adjust the flow channel structure, including: changing the flow channel cross-sectional shape, adjusting the flow channel size, optimizing the flow channel bending angle, and removing or adding obstacles in the flow channel; S73, re-mesh the adjusted flow channel to ensure that the mesh quality meets the simulation requirements; S74, set new boundary conditions and monitoring points.

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