Semi-closed cathode air-cooled fuel cell metal bipolar plate, stack, system and design method

Abstract

The invention belongs to the technical field of fuel cells, and particularly relates to a semi-closed cathode air-cooled fuel cell metal bipolar plate, an electric pile, a system and a design method. Active areas of a cathode plate, a cooling plate and an anode plate are overlapped to form an active area of the metal bipolar plate; the active area of the metal bipolar plate is divided into an inlet side low-current-density medium-voltage-drop area, a middle medium-current-density low-voltage-drop area and an outlet side high-current-density high-voltage-drop area; the fuel cell has the advantages of simple structure of an open cathode fuel cell and high power density of a closed cathode air cooling fuel cell, effectively avoids the problems of temperature, humidity and pollutant interference and the like caused by direct exposure of the open cathode structure to the external environment, and remarkably improves the environmental adaptability of the system; meanwhile, the defects that a traditional closed cathode air-cooled fuel cell system is complex in structure, high in cost, complex in control strategy and the like are overcome.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, specifically relating to a semi-enclosed cathode air-cooled fuel cell metal bipolar plate, stack, system, and design method. Background Technology

[0002] Air-cooled metal bipolar plate proton exchange membrane fuel cells have become an important solution for UAV power systems due to their outstanding advantages such as high power density and light weight. Currently, common air-cooled fuel cells are mainly divided into two types: open cathode structure and closed cathode structure. While open cathode fuel cells have a simple structure, their power density is relatively low and their environmental adaptability is weak. The reactant gas on the cathode side is in direct contact with the outside air, making it susceptible to interference from external environmental fluctuations such as temperature, humidity, and pollutants. This not only leads to unstable performance output but also seriously affects the long-term durability and lifespan of the battery. Closed cathode air-cooled fuel cells enhance environmental adaptability through a closed cathode structure, avoiding the direct impact of the external environment on the battery reaction. However, their systems typically require complex auxiliary equipment such as high-power air compressors, resulting in a significant increase in parasitic power and overall mass, thereby reducing the system's actual energy efficiency and power density advantage. Semi-closed cathode structures, on the other hand, combine the advantages of both, simplifying the system structure while maintaining high power density, and have great development potential. Summary of the Invention

[0003] The purpose of this invention is to provide a semi-enclosed cathode air-cooled fuel cell metal bipolar plate, stack, system, and design method, overcoming the contradiction between power density, environmental adaptability, and system simplicity in existing air-cooled fuel cells; optimizing the cathode flow channel and air circulation path, simplifying the system configuration, requiring only the addition of a fan to the open cathode to achieve decoupling of the reaction gas and cooling gas, while retaining the air filtration function, significantly reducing the complexity and cost of the battery system while ensuring performance improvement and lifespan extension.

[0004] To address the aforementioned technical problems, in a first aspect, the present invention provides a semi-enclosed cathode air-cooled fuel cell metal bipolar plate, comprising an anode plate, a cooling plate, and a cathode plate. The active regions of the cathode plate, cooling plate, and anode plate are stacked to form the active region of the metal bipolar plate. The active region of the metal bipolar plate is divided into an inlet-side low current density medium voltage drop region, a middle-side medium current density low voltage drop region, and an outlet-side high current density high voltage drop region. The inlet-side low current density medium voltage drop region, the middle-side medium current density low voltage drop region, and the outlet-side high current density high voltage drop region are all square. The inlet-side low current density medium voltage drop region is located at the lower part of the active region of the metal bipolar plate, the middle-side medium current density low voltage drop region is located at the middle part of the active region of the metal bipolar plate, and the outlet-side high current density high voltage drop region is located at the upper part of the active region of the metal bipolar plate. The active region based on the metal bipolar plate is divided into a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side. The corresponding positions on the cathode plate, cooling plate, and anode plate are also divided into a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side. An anode gas inlet is provided on one side of the low current density and medium voltage drop region on the inlet side, and an anode gas outlet is provided on one side of the high current density and high voltage drop region on the outlet side. The length and width of the active region of the metal bipolar plate are determined according to the following model: ; In the formula: The width of the active region of the metal bipolar plate; The width of the low current density, medium voltage drop region on the inlet side; The width of the low voltage drop region with medium current density in the middle section; The width of the high current density high voltage drop zone on the export side; is the length of the active region of the metal bipolar plate; The length of the voltage drop region at low current density on the inlet side. The length of the medium current density, low voltage drop region in the middle section. The length of the high current density and high voltage drop zone on the export side; For the anode flow channel cycle; This refers to the number of anode flow channels; The region of the voltage drop zone in the low current density at the inlet side is determined according to the following model: ; In the formula: is the length of the active region of the metal bipolar plate; The width of the active region of the metal bipolar plate; For the anode flow channel cycle; The number of anode flow channels; where and The configuration is based on a three-dimensional coordinate system, with the plane where the anode plate is located configured as the XOY plane, and the direction perpendicular to the anode plate as the Z axis; The region of low current density and low voltage drop in the central part is determined according to the following model: ; in, is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; This refers to the number of anode flow channels; The region of the high current density and high voltage drop zone on the outlet side is determined according to the following model: ; in, is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; This represents the number of anode flow channels.

[0005] Preferably, in the low current density and voltage drop region at the inlet side, a plurality of cathode channels are configured to cause the cathode reactive gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; In the central region with low current density and low voltage drop, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to tend to flow in the positive X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; In the high current density and high voltage drop region on the outlet side, several cathode channels are configured to cause the cathode reactive gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; Several cooling channels are configured in the low current density and medium pressure drop region at the inlet, the medium current density and low pressure drop region in the middle, and the high current density and high pressure drop region at the outlet to encourage the cooling gas to flow in the positive Y-axis direction, and the centerline of the cooling channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

[0006] Preferably, the centerlines of each flow channel in the low current density and medium voltage drop region on the inlet side, the medium current density and low voltage drop region in the middle, and the high current density and high voltage drop region on the outlet side are determined according to the following model: ; In the formula: For the first The centerline of the direct current path of the root cathode; Centerline of the cathode flow channel The projection onto the XOY plane forms an angle with the X-axis; The width of the active region of the metal bipolar plate; For the cathode flow channel period; For the first The centerline of the root anode flow channel; Centerline of the anode flow channel The projection onto the XOY plane forms an angle with the X-axis; is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; For the first The centerline of the root cooling channel; Centerline of the cooling channel The projection onto the XOY plane forms an angle with the X-axis; This is the cooling channel cycle.

[0007] Preferably, a fuel gas diversion transition structure is provided between the low current density and medium pressure drop zone at the inlet side of the anode plate and the medium current density and low pressure drop zone in the middle, so that the flow direction of the anode fuel gas changes from a tendency to flow in the negative X-axis direction to a tendency to flow in the positive X-axis direction; and a similar fuel gas diversion transition structure is provided between the medium current density and low pressure drop zone in the middle of the anode plate and the high current density and high pressure drop zone at the outlet side, so that the flow direction of the anode fuel gas changes from a tendency to flow in the positive X-axis direction to a tendency to flow in the negative X-axis direction. The parameters of the fuel gas diversion transition structure include the anode flow channel width. inner corner radius outer corner radius And satisfy: .

[0008] Preferably, the metal bipolar plate further includes an anode sealing strip for the anode plate and a cathode sealing strip for the cathode plate. The anode sealing strip seals the anode flow channels on the anode plate, and the cathode sealing strip seals the cathode flow channels and cooling flow channels on the cathode plate and cooling plate. The height of the anode sealing strip is [not specified]. The thickness of the cathode sealing strip is The anode sealing groove and the cathode sealing groove are respectively formed by folding the plate matrix of the anode plate and the plate matrix of the cathode plate, and are used to accommodate the anode sealing strip and the cathode sealing strip respectively, and their depths are both... , And satisfy: ; ; In the formula: This refers to the thickness of the substrate material for the anode and cathode plates. ; For cooling channel depth, ; The compression factor is 1. .

[0009] Preferably, the centerline of the cathode flow channel is set. Centerline of the anode flow channel The projection on the XOY plane forms an angle. The centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. ,but: The included angle within the low current density and medium voltage drop region on the inlet side Angle and cathode flow channel period Anode flow channel cycle If it is a variable, then the included angle satisfy included angle satisfy Cathode flow channel period satisfy Cathode flow channel period satisfy And satisfy: ; ; Therefore, the current density in the low current density and voltage drop region at the inlet side is determined by the following model: ; The cathode voltage drop in the low current density region at the inlet side is determined according to the following model: ; The current density in the middle region with low current density and low voltage drop is determined according to the following model: ; The cathode voltage drop in the medium current density, low voltage drop region of the central part is determined according to the following model: ; The current density in the high current density and high voltage drop zone on the outlet side is determined according to the following model: ; The cathode voltage drop in the high current density and high voltage drop zone on the outlet side is determined according to the following model: .

[0010] Secondly, the present invention provides a semi-enclosed cathode air-cooled fuel cell stack, including an end plate, an insulating plate, a current collector, and a stack core. The stack core includes a semi-enclosed cathode air-cooled fuel cell metal bipolar plate as described above. The stack core consists of metal bipolar plates and membrane electrode assemblies stacked periodically from top to bottom, ending with a metal bipolar plate.

[0011] Thirdly, the present invention provides a semi-enclosed cathode air-cooled fuel cell system, the battery system including a blower and a semi-enclosed cathode air-cooled fuel cell stack as described above, wherein the pressure range of the blower is 0-30 kPa.

[0012] Fourthly, the present invention provides a design method for a semi-enclosed cathode air-cooled fuel cell, applicable to a semi-enclosed cathode single cell comprising a metal bipolar plate of a semi-enclosed cathode air-cooled fuel cell as described above. The design method specifically includes: S1. Determine the optimization objective for a semi-enclosed cathode single cell. Design variables and design variable constraints, where p is the optimization objective index symbol, and optimization objective g1 is the total current density. I The optimization objective g2 is the total cathode voltage drop. Pa ; l To design variable index symbols, design variables. x 1 represents the cathode flow channel period. Design variables x 2 represents the anode flow channel cycle. Design variables x 3 is the centerline of the cathode flow channel. With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane Design variables x 4 is the centerline of the cathode flow channel. With the centerline of the cooling channel The included angle formed by the projection on the XOY plane The design variable constraints are: ,in and For the first l Upper and lower limits of a design variable; S2. Based on the initial settings in step S1, design multiple experimental schemes, and fit the performance values ​​of each optimization objective of the semi-enclosed cathode single cell to establish a second-order polynomial objective function for each optimization objective of the semi-enclosed cathode single cell. The second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell. As shown in the following formula: ; The second-order polynomial objective function of the optimization objective g2 of a semi-enclosed cathode single cell. As shown in the following formula: ; The second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell is... for: ; In the formula, The constant term coefficient of the total current density, Total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient; The second-order polynomial objective function of the optimization objective g2 of a semi-enclosed cathode single cell. for: ; In the formula, The constant term coefficient for the total cathode voltage drop is... Total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For cathode voltage drop Term coefficient; S3. Optimization Objectives Based on Semi-Enclosed Cathode Single Cells Second-order polynomial objective function Design variables for semi-enclosed cathode single cells: cathode flow channel period x 1 Anode flow channel cycle x 2 Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3 Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4 Classify the strategies to obtain a set of combinations; S4. Determine the design variables for the pre-optimized semi-enclosed cathode single cell: cathode flow channel period. x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x The value of 4 is determined, and the initial strategy set for each optimization objective of the semi-enclosed cathode single cell is determined based on the strategy set combination obtained in step S3. and complement ; S5, the total current density of a semi-enclosed cathode single cell. g 1. Total cathode voltage drop g2. To optimize the objectives, a multi-objective benefit model for a semi-enclosed cathode single cell is established. The combined weighting method is used to calculate the combined weight coefficients of each optimization objective in the multi-objective benefit model for the semi-enclosed cathode single cell. The benefit functions of each optimization objective for the semi-enclosed cathode single cell are shown in the following equation: ; In the formula: For the semi-enclosed cathode single cell p The optimal strategy set for each optimization objective; For the semi-enclosed cathode single cell p An initial policy set for each optimization objective; For the semi-enclosed cathode single cell p The complement of each optimization objective; For the semi-enclosed cathode single cell p A second-order polynomial objective function with optimization objectives; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; In a semi-enclosed cathode single cell, except for the first p The second-order polynomial objective function for all optimization objectives other than the first optimization objective; In a semi-enclosed cathode single cell, except for the first p The combined weight coefficients of the remaining optimization objectives besides the first optimization objective; The combined weighting method first calculates the subjective weight coefficients of each optimization objective using the analytic hierarchy process (AHP), then calculates the objective weight coefficients using the entropy weighting method, and finally calculates the combined weight coefficients of each optimization objective in the multi-objective benefit model of a semi-closed cathode single cell. The formula for the combined weighting method is shown below: ; In the formula: This indicates the semi-enclosed cathode single cell. p The subjective weight coefficients of each optimization objective; This indicates the semi-enclosed cathode single cell. p Objective weighting coefficients for each optimization objective; S6. After optimizing the reward function of each optimization objective of the semi-enclosed cathode single cell using an optimization algorithm, the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell is obtained. And the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell. The combined cathode flow channel period is obtained for a semi-enclosed cathode single cell. x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY planex 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4. Optimal combination of design variables ; S7. Based on the optimal design variable set combination obtained for the semi-enclosed cathode single cell. Design a semi-enclosed cathode single cell and obtain the optimization objectives for the optimized semi-enclosed cathode single cell: total current density. g 1. Total cathode voltage drop g The performance values ​​of the 2-cell semi-enclosed cathode single cell were evaluated, and a comprehensive score was given for the semi-enclosed cathode single cell before and after optimization. The comprehensive performance score of the semi-enclosed cathode single cell before optimization was obtained. And the comprehensive performance score of the optimized semi-enclosed cathode single cell The scoring formula is shown below: ; In the formula: S represents the overall performance score; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; The first semi-enclosed cathode single cell after normalization treatment p Performance values ​​of each optimization objective; S8. Compare and optimize the overall performance scores of the semi-enclosed cathode single cell before and after optimization. Then return to step S4 and use the optimal design variable set combination for the semi-enclosed cathode single cell. Replace the original design variable values ​​of the semi-enclosed cathode single cell with the current design variable values, and redesign accordingly; if The optimization ends when the optimal combination of design variables for the semi-enclosed cathode single cell is output. Middle cathode flow channel period x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4. Values ​​of each design variable.

[0013] The beneficial effects of this invention are as follows: This invention divides the active region of a metal bipolar plate into three functional zones, exploring the specific arrangement of the anode, cooling, and cathode channels in each zone. By parameterizing the centerline angles of each channel and constraining their range, the relative flow directions of the cathode reactant gas, anode fuel gas, and cooling gas are organized in different zones, improving the overall current density distribution and effectively reducing the cathode voltage drop. Simultaneously, the flow paths of the cathode channel and cathode reactant gas are optimized, allowing the metal bipolar plate to achieve decoupling of the cathode reactant gas and cooling gas simply by adding a blower to the open cathode design. This retains the air filtration function inherent in existing fuel cells, significantly reducing complexity and manufacturing costs while ensuring improved performance and extended lifespan of the metal bipolar plate.

[0014] Furthermore, the present invention also provides a fuel cell stack and system scheme using the above-mentioned metal bipolar plate configuration, as well as a multi-objective optimization design method based on "current density-cathode voltage drop", which allows for calculable and optimizable selection of key geometric parameters, achieving a trade-off between high current density and low cathode voltage drop, reducing trial and error iterations and improving engineering implementation efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of the metal bipolar plate in this invention; Figure 2 This is a schematic diagram showing the regional division and flow direction of the anode plate, cooling plate, and cathode plate in this invention; Figure 3 This is a schematic diagram of the anode fuel gas diversion transition structure on the anode plate in this invention; Figure 4 The included angle within the low current density and medium voltage drop region on the inlet side of this invention. Angle Angle and included angle Angle Relationship diagram; Figure 5 The polarization curves and power density curves for current density and power density under voltages of 0.9-0.5V are shown in the simulation process of this invention. Figure 6This is a top view of the cathode sealing strip in this invention; Figure 7 This is a top view of the anode sealing strip in this invention; Figure 8 This is a schematic diagram of the cross-sectional structure of the cathode sealing groove and the anode sealing groove in this invention; Figure 9 This is a partial schematic diagram of the semi-enclosed cathode air-cooled fuel cell system provided by the present invention; Figure 10 for Figure 9 Schematic diagram of the partial explosion at point A in the middle; Figure 11 This is a schematic diagram of the semi-enclosed cathode air-cooled fuel cell system provided by the present invention.

[0017] In the diagram: Anode plate 1, Anode gas inlet 101, Anode gas outlet 102, Anode inlet in the low current density and medium pressure drop zone on the inlet side 103, Anode outlet in the low current density and medium pressure drop zone on the inlet side 104, Anode outlet in the medium current density and low pressure drop zone in the middle 105, Anode outlet in the high current density and high pressure drop zone on the outlet side 106; Cooling plate 2; Cathode plate 3; Upper end plate 4; Upper insulating plate 5; Upper current collector plate 6; Core 7; Lower current collector plate 8; Lower insulating plate 9; Lower end plate 10; Membrane electrode 11; Support mesh 12; Stack 13; Blower 14; Fuel gas circulation pump 15; Fuel gas injector 16; Exhaust valve 17; Cooling fan 18; DC-DC converter 19. Detailed Implementation

[0018] 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. 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.

[0019] In the description of this invention, it should be noted that the terms "center," "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. 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. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] This application proposes a bipolar plate, stack, system, and design method applicable to semi-enclosed cathode air-cooled fuel cell. At the metal bipolar plate level, this application adopts a structure composed of cathode sealing strips, cathode plates, cooling plates, anode plates, and anode sealing strips. The cathode plate is provided with cathode flow channels for cathode reaction airflow, the cooling plate is provided with cooling flow channels for cooling gas flow, and the anode plate is provided with anode flow channels for anode fuel gas flow. Based on the upper, middle, and lower three-layer structure of the anode plate, cooling plate, and cathode plate as a metal bipolar plate, the active area of ​​the metal bipolar plate is further divided into regions to form a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side, so as to achieve synergy between mass transfer and heat dissipation.

[0021] Furthermore, this application constrains the flow trends of cathode reaction air, anode fuel gas, and cooling gas in different zones, and incorporates an anode fuel gas deflection transition structure to reduce local losses during the deflection process. This ensures the continuity of the flow channel arrangement in each zone while improving the current density distribution, thereby effectively reducing the cathode voltage drop.

[0022] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0023] like Figure 1-2As shown, in the prior art, a metal bipolar plate includes an anode plate 1, a cooling plate 2, and a cathode plate 3, and the anode plate 1, cooling plate 2, and cathode plate 3 are arranged in a three-layer structure (upper, middle, and lower). The cathode plate 3, cooling plate 2, and anode plate 1 are respectively provided with a number of cathode flow channels, a number of cooling flow channels, and a number of anode flow channels. The cathode plate 3, cooling plate 2, and anode plate 1 are all provided with active areas and channel areas, and the active areas on the cathode plate 3, cooling plate 2, and anode plate 1 correspond to each other in the superposition space. The three active areas on the cathode plate 3, cooling plate 2, and anode plate 1 together constitute the active area of ​​the metal bipolar plate. Two through holes are arranged in a centrally symmetrical manner in the channel area of ​​the anode plate 1, and these two through holes are respectively configured as an anode gas inlet 101 and an anode gas outlet 102.

[0024] like Figure 1 and Figure 2 As shown, a semi-enclosed cathode air-cooled fuel cell metal bipolar plate has an active area divided into an inlet-side low current density medium voltage drop region I, a middle-side medium current density low voltage drop region II, and an outlet-side high current density high voltage drop region III. The inlet-side low current density medium voltage drop region I, the middle-side medium current density low voltage drop region II, and the outlet-side high current density high voltage drop region III are all square. The inlet-side low current density medium voltage drop region I is located in the lower part of the active area of ​​the metal bipolar plate, the middle-side medium current density low voltage drop region II is located in the middle of the active area of ​​the metal bipolar plate, and the outlet-side high current density high voltage drop region III is located in the upper part of the active area of ​​the metal bipolar plate.

[0025] The active region based on the metal bipolar plate is divided into an inlet-side low current density and medium voltage drop region I, a middle-side medium current density and low voltage drop region II, and an outlet-side high current density and high voltage drop region III. The corresponding positions on the cathode plate 3, cooling plate 2, and anode plate 1 are also divided into an inlet-side low current density and medium voltage drop region I, a middle-side medium current density and low voltage drop region II, and an outlet-side high current density and high voltage drop region III. An anode gas inlet 101 is arranged on one side of the inlet-side low current density and medium voltage drop region I, and an anode gas outlet 102 is arranged on one side of the outlet-side high current density and high voltage drop region III.

[0026] Specifically, based on this, for anode plate 1, the anode fuel gas flows within several anode channels configured on anode plate 1; the anode fuel gas starts from anode gas inlet 101, enters the low current density medium pressure drop zone I at the lower part of anode plate 1 from the anode inlet 103 in the low current density medium pressure drop zone on the inlet side, and then flows out from the anode outlet 104 in the low current density medium pressure drop zone on the inlet side; taking the anode outlet 104 in the low current density medium pressure drop zone on the inlet side as the anode inlet in the middle medium current density low pressure drop zone, the anode fuel gas flows out from the middle medium current density... The low-pressure-drop zone anode inlet enters the middle medium-current-density low-pressure-drop zone II set in the middle of the anode plate 1, and then flows out from the anode outlet 105 of the middle medium-current-density low-pressure-drop zone; taking the anode outlet 105 of the middle medium-current-density low-pressure-drop zone as the anode inlet of the outlet side high-current-density high-pressure-drop zone, the anode fuel gas enters the outlet side high-current-density high-pressure-drop zone III set in the upper part of the anode plate 1 from the anode inlet of the outlet side high-current-density high-pressure-drop zone, and then flows out from the anode outlet 106 of the outlet side high-current-density high-pressure-drop zone, and then the anode fuel gas flows out of the anode plate 1 from the anode gas outlet 102.

[0027] For cathode plate 3, the cathode reaction gas flows in the cathode flow channel configured on cathode plate 3; the cathode reaction gas enters cathode plate 3 from the left edge and flows out from the right edge of cathode plate 3.

[0028] For the cooling plate 2, the cooling gas flows in the cooling channels configured on the cooling plate 2; the cooling gas enters the cooling plate 2 from the lower edge and flows out from the upper edge of the cooling plate 2.

[0029] A three-dimensional coordinate system is configured within the metal bipolar plate, such as Figure 2 As shown, the plane where the anode plate 1 is located is configured as the XOY plane, and the direction perpendicular to the anode plate 1 is the Z-axis. The origin O is set at the edge inflection point of the active area on the anode plate 1, and the projection of the active area of ​​the anode plate 1 on the XOY plane is placed in the first quadrant of the XOY plane coordinate system.

[0030] Based on the configured three-dimensional coordinate system, the active region width of the metal bipolar plate is set to... , The anode flow channel period is , Cathode flow channel period , Furthermore, in this application, the anode flow channel cycle is... With cathode flow channel period They are always equal, therefore: The length and width of the active region of a metal bipolar plate are determined according to the following model: (Formula 1) In the formula: The width of the active region of the metal bipolar plate; The width of the low current density, medium voltage drop region on the inlet side; The width of the low voltage drop region with medium current density in the middle section; The width of the high current density high voltage drop zone on the export side; is the length of the active region of the metal bipolar plate; The length of the voltage drop region at low current density on the inlet side. This is the central region with medium current density and low voltage drop. The length of the high current density and high voltage drop zone on the export side; For the anode flow channel cycle; This represents the number of anode flow channels.

[0031] The region of low current density and medium voltage drop zone I on the inlet side is determined according to the following model: (Formula 2) In the formula: is the length of the active region of the metal bipolar plate; The width of the active region of the metal bipolar plate; For the anode flow channel cycle; The number of anode flow channels. Once the length and width of the active area are determined, they are arranged as needed to fill the active area.

[0032] The region of the medium current density and low voltage drop zone II in the central part is determined according to the following model: (Formula 3) in, is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; This represents the number of anode flow channels.

[0033] The region of high current density and high voltage drop zone III on the outlet side is determined according to the following model: (Formula 4) in, is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; This represents the number of anode flow channels.

[0034] It should be noted that, since the prior art description of this application includes the description that the active region of the metal bipolar plate is composed of three active regions on the anode plate 1, the cooling plate 2, and the cathode plate 3 stacked in sequence, unless otherwise stated, the active region described below refers to the active region of the metal bipolar plate.

[0035] Specifically, such as Figure 2 As shown, in the low current density and medium voltage drop region I at the inlet side, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

[0036] In the middle region, within the low current density and low voltage drop zone II, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to tend to flow in the positive X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

[0037] In the high current density and high voltage drop zone III on the outlet side, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

[0038] Several cooling channels are configured in the low current density and medium pressure drop zone I on the inlet side, the medium current density and low pressure drop zone II in the middle, and the high current density and high pressure drop zone III on the outlet side to encourage the cooling gas to flow in the positive Y-axis direction, and the centerline of the cooling channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

[0039] The centerlines of each flow channel in the inlet side low current density medium voltage drop zone I, the middle medium current density low voltage drop zone II, and the outlet side high current density high voltage drop zone III are determined according to the following model: (Formula 5) In the formula: For the first The centerline of the direct current path of the root cathode; Centerline of the cathode flow channel The projection onto the XOY plane forms an angle with the X-axis; The width of the active region of the metal bipolar plate; For the cathode flow channel period; For the first The centerline of the root anode flow channel; Centerline of the anode flow channel The projection onto the XOY plane forms an angle with the X-axis; is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; For the first The centerline of the root cooling channel; Centerline of the cooling channel The projection onto the XOY plane forms an angle with the X-axis; This is the cooling channel cycle.

[0040] In each of the aforementioned regions, the centerline of the cathode flow channel The angles formed by the projection onto the XOY plane and the X-axis, and the centerline of the anode flow channel. The angles formed by the projection on the XOY plane and the X-axis, and the centerline of the cooling channel. The angle formed by the projection on the XOY plane and the X-axis can ensure the integrity of the flow channel within the corresponding range. Beyond this range, the flow channel may experience interruptions.

[0041] In general, given the expressions for the centerlines of each flow channel in each region, the actual extension direction of each flow channel in each region can be obtained, and thus the flow trends of each gas in different flow channels in different regions can be derived, such as... Figure 2 As shown, in the low current density and low voltage drop zone I on the inlet side, the anode fuel gas of the anode plate 1 and the cathode reaction gas of the cathode plate 3 flow in opposite directions. This opposite cross flow can achieve triple homogenization of the concentration field, temperature field and water distribution field, greatly reducing various polarization losses, thereby achieving higher current density and lower cathode voltage drop.

[0042] In the medium current density and low voltage drop zone II in the middle part, the fuel gas of the anode plate 1 and the cathode reaction gas of the cathode plate 3 flow in the same direction and cross each other. This same direction and cross flow can realize the synchronous adjustment of the flow rate of the cathode reaction gas and the anode fuel gas under variable load conditions, and the synchronous changes in reaction rate, temperature and water distribution with small response lag.

[0043] In the high current density and high pressure drop zone III on the outlet side, the anode fuel gas of anode plate 1 and the cathode reaction gas of cathode plate 3 flow in opposite directions. The effect achieved by this opposite cross-flow is the same as that achieved by the opposite cross-flow of the anode fuel gas of anode plate 1 and the cathode reaction gas of cathode plate 3 in the low current density and medium pressure drop zone I on the inlet side.

[0044] In addition, based on the actual arrangement of the flow channels in each region, it can be concluded that the anode flow channel has a transition structure that allows the gas to be redirected, such as... Figure 3 As shown, a fuel gas diversion transition structure is provided between the low current density and medium pressure drop zone I on the inlet side of the anode plate 1 and the medium current density and low pressure drop zone II in the middle, so that the flow direction of the anode fuel gas changes from a tendency to flow in the negative X-axis direction to a tendency to flow in the positive X-axis direction; and a similar fuel gas diversion transition structure is provided between the medium current density and low pressure drop zone II in the middle of the anode plate 1 and the high current density and high pressure drop zone III on the outlet side, so that the flow direction of the anode fuel gas changes from a tendency to flow in the positive X-axis direction to a tendency to flow in the negative X-axis direction.

[0045] The parameters of the fuel gas diversion transition structure include the anode flow channel width. , inner corner radius , outer corner radius And satisfy: (Formula 6) At this point, the arrangement of each flow channel in each region, the formula for expressing the centerline, and the centerline of the cathode flow channel have been completed. The angles formed by the projection onto the XOY plane and the X-axis, and the centerline of the anode flow channel. The angles formed by the projection on the XOY plane and the X-axis, and the centerline of the cooling channel. After defining and explaining structural parameters such as the angle formed by the projection on the XOY plane and the X-axis, this application, in order to further clarify the influence of key structural parameters on the performance indicators of the metal bipolar plate, uses the centerline of the cathode flow channel in the low current density, medium voltage drop region I on the inlet side. Centerline of the anode flow channel The included angle formed by the projection on the XOY plane The centerline of the cathode flow channel Centerline of the cooling channel The included angle formed by the projection on the XOY plane and cathode flow channel period Anode flow channel cycle A multiphysics coupled simulation model was constructed to obtain the relationship between the above factors and current density and cathode voltage drop; at this time, the included angle satisfy included angle satisfy Cathode flow channel period satisfy Anode flow channel cycle satisfy ,like Figure 4 As shown, the following conditions are met: (Formula 7) (Formula 8) Therefore, after obtaining the definitions and value ranges of the specific variables, a simulation experiment was designed to obtain the current density and cathode voltage drop in each region under the above conditions, as shown in Tables 1 and 2 below. It should be noted that regions I-III in the tables represent the low current density and medium voltage drop region I on the inlet side, the medium current density and low voltage drop region II in the middle, and the high current density and high voltage drop region III on the outlet side, respectively. Furthermore, the simulation process uses the controlled variable method, with the included angle... Cathode flow channel period Anode flow channel cycle Angle With two variables fixed, the influence of a single variable on current density and cathode voltage drop is investigated.

[0046]

[0047]

[0048] Therefore, multi-dimensional simulation results of current density and cathode voltage drop in different regions of the metal bipolar plate are obtained using simulation methods, and the simulation results in each region are specifically expressed by the fitting formula as follows: The current density in the low current density region I at the inlet side is determined according to the following model: (Formula 9) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0049] The cathode voltage drop in region I, with low current density at the inlet side, is determined according to the following model: (Formula 10) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0050] The current density in the low voltage drop region II of the middle current density area is determined according to the following model: (Formula 11) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0051] The cathode voltage drop in the medium current density, low voltage drop region II is determined according to the following model: (Formula 12) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0052] The current density of the high current density and high voltage drop zone III on the outlet side is determined according to the following model: (Formula 13) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0053] The cathode voltage drop in the high current density and high voltage drop zone III on the outlet side is determined according to the following model: (Formula 14) In the formula: For the cathode flow channel period, Anode flow channel cycle , ; Centerline of the cathode flow channel Centerline of the anode flow channel The projection on the XOY plane forms an angle. ; Centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. , .

[0054] Based on the above simulation experiment and the fitted expressions, the mechanism of region division for the active area of ​​the metal bipolar plate in this application can be explained. Taking Equations 9 and 10 as examples, since the current density and cathode voltage drop of each region are different during different cathode flow cycles... Anode flow channel cycle Angle and included angle The same pattern of change is observed below, according to Figure 2 Based on the positional relationship of the various regions, Region I is named the inlet-side low current density medium voltage drop region, Region II is named the central medium current density low voltage drop region, and Region III is named the outlet-side high current density high voltage drop region. Among these, according to... Figure 2 The positions of each region shown are related to the positions of the anode gas inlet 101 and the anode gas outlet 102, thus obtaining positional descriptions such as "inlet side", "outlet side" and "middle". On the other hand, the distribution law of current density in each region and the evolution characteristics of cathode voltage drop under the flow field matching mode are clarified, ultimately laying a solid theoretical and data foundation for the multi-objective optimization of total current density and total cathode voltage drop.

[0055] This embodiment is also based on the specific configuration of the metal bipolar plate of a semi-enclosed cathode air-cooled fuel cell described above, combined with the investigated included angle. Angle Cathode flow channel period With anode flow channel cycle Within a certain range, considering the relationship between current density and cathode voltage drop, and taking into account the conflict between current density and cathode voltage drop in a semi-enclosed cathode single cell under actual conditions, and the inability to effectively reconcile this conflict while improving the performance of the semi-enclosed cathode single cell, this invention adopts a semi-enclosed cathode air-cooled fuel cell design method to solve this problem.

[0056] First, this application uses the aforementioned simulation experiments to obtain the design variables that influence the determined optimization objective, namely the included angle. Angle Cathode flow channel period and anode flow channel cycle Based on the second-order polynomial objective function of each optimization objective of the semi-enclosed cathode single cell, this invention obtains the influence factor matrix of each design variable of the semi-enclosed cathode single cell. Secondly, based on the fuzzy clustering method of fuzzy equivalence relations, this invention clusters the influence factor matrix of each design variable of the semi-enclosed cathode single cell to solve for the design variable values ​​when the comprehensive performance of the semi-enclosed cathode single cell reaches its optimal level. Subsequently, based on the combined weighting method, the optimal strategy set of each optimization objective of the semi-enclosed cathode single cell is obtained, and the optimal strategy sets of each optimization objective of the semi-enclosed cathode single cell are combined to obtain the optimal design variable set combination for the semi-enclosed cathode single cell. Finally, by comparing the comprehensive performance scores of the semi-enclosed cathode single cell before and after optimization, the values ​​of each design variable when the comprehensive performance of the semi-enclosed cathode single cell reaches its optimal level are obtained. This invention not only achieves the goal of improving the performance of the semi-enclosed cathode single cell, but also effectively reconciles the conflicting performance of each optimization objective of the semi-enclosed cathode single cell.

[0057] S1. Determine the optimization objective for a semi-enclosed cathode single cell. Design variables and design variable constraints, where p is the optimization objective index symbol, and optimization objective g1 is the total current density. I The optimization objective g2 is the total cathode voltage drop. Pa ; l To design variable index symbols, design variables. x 1 represents the cathode flow channel period. Design variables x 2 represents the anode flow channel cycle. Design variables x 3 is the centerline of the cathode flow channel. With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane Design variables x 4 is the centerline of the cathode flow channel. With the centerline of the cooling channel The included angle formed by the projection on the XOY plane The design variable constraints are: ,in and For the first l Upper and lower limits of a design variable.

[0058] In this embodiment, the design variables and design variable constraints of the semi-enclosed cathode single cell are shown in Table 3:

[0059] Based on the established optimization objectives, design variables, and constraints of the closed-cathode single cell, 16 experimental schemes were designed, as shown in Table 4.

[0060] S2. Based on the initial settings in step S1, design multiple experimental schemes, and fit the performance values ​​of each optimization objective of the semi-enclosed cathode single cell to establish a second-order polynomial objective function for each optimization objective of the semi-enclosed cathode single cell. The second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell. As shown in the following formula: (Formula 15) The second-order polynomial objective function of the optimization objective g2 of a semi-enclosed cathode single cell. As shown in the following formula: (Formula 16) In this application, the second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell is... Specifically: (Formula 17) In this application, the second-order polynomial objective function of the optimization objective g2 of the semi-enclosed cathode single cell is... Specifically: (Formula 18) S3. Optimization Objectives Based on Semi-Enclosed Cathode Single Cells g p Second-order polynomial objective function Design variables for semi-enclosed cathode single cells: cathode flow channel period x1 Anode flow channel cycle x 2 Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3 Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4 Classify the strategies to obtain a set of combinations.

[0061] In this application, step S3 specifically involves the following steps: S31. Optimization objective based on semi-enclosed cathode single cell g p Second-order polynomial objective function f p By taking the partial derivatives of each design variable for the semi-enclosed cathode single cell, the optimization objective of the semi-enclosed cathode single cell can be obtained. g p Second-order polynomial objective function f p Partial derivative formulas for each design variable The partial derivative formula As shown in the following formula: (Formula 19) In the formula, To find the partial derivative function, n Indicates the number of design variables. m To optimize the number of targets.

[0062] S32. Optimization objective of semi-enclosed cathode single cell using optimization algorithm. g p Second-order polynomial objective function f p A single-objective optimization solution is performed to obtain the optimization objective of the semi-enclosed cathode single cell. g p Second-order polynomial objective function f p Single-objective optimal solution ,in ={ }

[0063] Preferably, this application uses a genetic algorithm to optimize the objective of the semi-enclosed cathode single cell. g p Second-order polynomial objective function f pPerform single-objective optimization to solve the problem.

[0064] In this embodiment of the application, the optimization objective of the semi-enclosed cathode single cell obtained based on the 16 experimental schemes in Table 4 is... g p Second-order polynomial objective function f p Single-objective optimal solution As shown below: ① The second-order polynomial objective function of total current density f 1 Single-objective optimal solution for: (Formula 20) ② The second-order polynomial objective function of the total pressure drop f Single-objective optimal solution of 2 for: (Formula 21) S33, Optimization objective of semi-enclosed cathode single cell g p Second-order polynomial objective function f p Single-objective optimal solution Substituting into the partial derivative formula In this process, the influence factor matrix B of each design variable for a semi-enclosed cathode single cell is constructed, and the influence factor matrix B is shown in the following formula: (Formula 22) In this embodiment of the application, the influence factor matrix B of each design variable of the semi-enclosed cathode single cell obtained based on the 16 experimental schemes in Table 4 is shown below: (Formula 23) S34. Perform fuzzy clustering on the influence factor matrix B of each design variable of the semi-enclosed cathode single cell to obtain the strategy set combination, where the strategy set combination is shown in the following formula: (Formula 24) In this application, the specific steps of performing fuzzy clustering processing on the influence factor matrix B of each design variable of the semi-enclosed cathode single cell in step S34 are as follows: S341. Transform the influence factor matrix B of each design variable of the semi-enclosed cathode single cell to obtain the standardized matrix B1. S342. The fuzzy similarity matrix R is obtained by applying the Euler distance method to the standardized matrix B1. S343. Perform self-squaring synthesis on the fuzzy similarity matrix R to obtain the transitive closure matrix t(R); S344. Based on the determined number m of optimization objectives for a semi-enclosed cathode single cell, select an appropriate confidence level k∈[0,1] to truncate the transitive closure matrix t(R), obtaining the truncation matrix. Therefore, based on the cut matrix The design variables of the semi-enclosed cathode single cell are categorized into m sets of strategies to obtain the strategy set combination.

[0065] In this embodiment of the application, the standardized matrix B1 obtained based on the 16 experimental schemes in Table 4 is: (Formula 25) In this embodiment of the application, the fuzzy similarity matrix R obtained based on the 16 experimental schemes in Table 4 is: (Formula 26) In this embodiment of the application, the transitive closure matrix t(R) obtained based on the 16 experimental schemes in Table 4 is: (Formula 27) In this embodiment of the application, the number of optimization targets for the semi-enclosed cathode single cell is m=2, and the confidence level is selected. k =0.9205 is used to truncate the transitive closure matrix t(R), resulting in the truncation matrix. for: (Formula 28) Subsequently, based on the cut matrix Design variables of semi-enclosed cathode single cell Classified into 2 policy sets: ,{ }

[0066] Preferably, the number of strategy sets in step S34 is consistent with the number of optimization objectives for the semi-enclosed cathode single cell.

[0067] In this embodiment of the application, there are two optimization objectives for the semi-enclosed cathode single cell. Therefore, after performing fuzzy clustering on the influence factor matrix B of each design variable of the semi-enclosed cathode single cell in step S34, the number of strategy sets in the obtained strategy set combination is also two.

[0068] In this embodiment of the application, the strategy set is combined as follows: ,in , .

[0069] S4. Determine the design variables for the pre-optimized semi-enclosed cathode single cell: cathode flow channel period. x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x The value of 4 is determined, and the optimal target total current density of the semi-enclosed cathode single cell is determined based on the strategy set combination obtained in step S3. g 1. Total cathode voltage drop g 2's initial strategy set and complement .

[0070] In this application, the complement of each optimization objective for the semi-enclosed cathode single cell is provided. The initial policy set for the remaining optimization objectives The union of .

[0071] In this embodiment, the design variables of the semi-enclosed cathode single cell—the cathode flow channel period—are optimized. x 1. Anode flow channel cycle x 2. Angle between cathode and anode flow channels x 3. Angle between cathode flow channel and cooling flow channel x The initial values ​​of 4 are 1.2, 1.6, 0, and 87, respectively. Therefore, the initial strategy set for the total current density is... Initial strategy set for total pressure drop As shown below: (Formula 29) (Formula 30) Correspondingly, the complement of the total current density Supplement of total pressure drop As shown below: (Formula 31) (Formula 32) S5, the total current density of a semi-enclosed cathode single cell. g 1. Total cathode voltage drop g 2. To optimize the objectives, a multi-objective benefit model for a semi-enclosed cathode single cell is established. The combined weighting method is used to calculate the combined weight coefficients of each optimization objective in the multi-objective benefit model for the semi-enclosed cathode single cell. The benefit functions of each optimization objective for the semi-enclosed cathode single cell are shown in the following equation: (Formula 33) In the formula: For the semi-enclosed cathode single cell p The optimal strategy set for each optimization objective; For the semi-enclosed cathode single cell p An initial policy set for each optimization objective; For the semi-enclosed cathode single cell p The complement of each optimization objective; For the semi-enclosed cathode single cell p A second-order polynomial objective function with optimization objectives; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; In a semi-enclosed cathode single cell, except for the first p The second-order polynomial objective function for all optimization objectives other than the first optimization objective; In a semi-enclosed cathode single cell, except for the first p The combined weight coefficients of the remaining optimization objectives besides the first optimization objective.

[0072] For example, in this embodiment of the application, two optimization objectives are determined. When calculating the profit function of the first optimization objective, at this time... Let be the second-order polynomial objective function for the first optimization objective of a semi-enclosed cathode single cell. The combined weighting coefficients represent the first optimization objective for a semi-enclosed cathode single cell. Let be the second-order polynomial objective function for the second optimization objective of a semi-enclosed cathode single cell. These are the weighting coefficients for the second optimization objective of the semi-enclosed cathode single cell; when calculating the payoff function for the second optimization objective, at this time... Let be the second-order polynomial objective function for the second optimization objective of a semi-enclosed cathode single cell. The weighting coefficients are for the second optimization objective of the semi-enclosed cathode single cell. Let be the second-order polynomial objective function for the first optimization objective of a semi-enclosed cathode single cell. The combined weighting coefficients are the first optimization objective for the semi-enclosed cathode single cell.

[0073] In this application, the combined weighting method first calculates the total current density using the analytic hierarchy process (AHP). g 1 and total cathode voltage drop g Subjective weighting coefficients of 2, and calculation of total current density using the entropy weighting method. g 1 and total cathode voltage drop g 2. Objective weighting coefficients are used, and then the total current density in the multi-objective benefit model of the semi-enclosed cathode single cell is calculated. g 1 and total cathode voltage drop g The combined weighting coefficients of 2 are calculated using the following formula: (Formula 34) In the formula: This indicates the semi-enclosed cathode single cell. p The subjective weight coefficients of each optimization objective; This indicates the semi-enclosed cathode single cell. p Objective weight coefficients for each optimization objective.

[0074] In this embodiment, the combined weighting coefficients of each optimization objective for the semi-enclosed cathode single cell are shown in Table 5:

[0075] S6. After optimizing the reward function of each optimization objective of the semi-enclosed cathode single cell using an optimization algorithm, the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell is obtained. And the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell. The optimal design variable set combination for a semi-enclosed cathode single cell is obtained after combination. ; In this application, the optimization algorithm used in step S6 is a genetic algorithm.

[0076] In this embodiment, the optimal design variable set combination for a semi-enclosed cathode single cell is described. for: (Formula 35) S7. Based on the optimal design variable set combination obtained for the semi-enclosed cathode single cell. Design a semi-enclosed cathode single cell and obtain the optimized total current density of the semi-enclosed cathode single cell. g 1. Total cathode voltage drop g The performance values ​​of the 2-cell semi-enclosed cathode single cell were evaluated, and a comprehensive score was given for the semi-enclosed cathode single cell before and after optimization. The comprehensive performance score of the semi-enclosed cathode single cell before optimization was obtained. And the comprehensive performance score of the optimized semi-enclosed cathode single cell The scoring formula is shown below: (Formula 36) In the formula: S represents the overall performance score; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; The first semi-enclosed cathode single cell after normalization treatment p The performance value of each optimization objective.

[0077] In this embodiment of the application, by substituting the combined weight coefficients of each optimization objective of the semi-enclosed cathode single cell obtained in Table 5 into the scoring formula, we can obtain: (Formula 37) S8. Compare and optimize the overall performance scores of the semi-enclosed cathode single cell before and after optimization. Then return to step S4 and use the optimal design variable set combination for the semi-enclosed cathode single cell. Replace the original design variable values ​​of the semi-enclosed cathode single cell with the current design variable values, and redesign accordingly; if The optimization ends when the optimal combination of design variables for the semi-enclosed cathode single cell is output. Middle cathode flow channel period x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4. Values ​​of each design variable.

[0078] In this embodiment, the performance values ​​of each optimization target of the semi-enclosed cathode single cell before and after optimization are shown in Table 6. Substituting the performance values ​​of each optimization target and design variable values ​​of the semi-enclosed cathode single cell before optimization in Table 6 into the scoring formula, the comprehensive performance score of the semi-enclosed cathode single cell before optimization is obtained. The value is 0.739944878. Substituting the performance values ​​of each optimization objective and design variable values ​​of the optimized semi-enclosed cathode single cell from Table 6 into the scoring formula, the comprehensive performance score of the optimized semi-enclosed cathode single cell is obtained. 0.939987537 > =0.739944878, therefore the game ends; furthermore, according to the formula It can be seen that the overall performance of the optimized semi-enclosed cathode single cell is improved by 27.03% compared with that of the un-optimized semi-enclosed cathode single cell.

[0079]

[0080] The current density and power density calculated from the simulation before and after optimization are plotted as follows: Figure 5 As shown, the performance of the semi-enclosed cathode single cell is improved under high power density conditions.

[0081] In summary, the semi-closed cathode air-cooled fuel cell design method provided in this embodiment not only achieves the goal of improving fuel cell performance, but also effectively reconciles the conflicting performance of various optimization objectives of the fuel cell. At the same time, this embodiment effectively solves the problem of conflicting multi-objective performance in the flow channel configuration parameters of the metal bipolar plate of the fuel cell, and can provide a reference for multi-objective optimization design in the field of fuel cells.

[0082] Having thus far obtained the arrangement of the flow channels in the three regions of the metal bipolar plate and the optimal arrangement parameters, this application also studies the sealing problem of the metal bipolar plate in actual use, such as... Figure 6-8 As shown, specifically: The metal bipolar plate also features an anode sealing strip for the anode plate 1 and a cathode sealing strip for the cathode plate 3. The anode sealing strip seals the anode flow channels on the anode plate 1, and the cathode sealing strip seals the cathode flow channels and cooling flow channels on the cathode plate 3 and cooling plate 2. The height of the anode sealing strip is [missing information]. The thickness of the cathode sealing strip is The anode sealing groove and the cathode sealing groove are respectively formed by folding the plate matrix of the anode plate 1 and the plate matrix of the cathode plate 3. The anode sealing groove and the cathode sealing groove are used to fit the anode sealing strip and the cathode sealing strip respectively, and their depths are both... , And satisfy: (Formula 38) (Formula 39) In the formula: This refers to the thickness of the substrate material for the anode and cathode plates. ; For cooling channel depth, ; The compression factor is 1. Within the aforementioned range, the anode sealing strip and the cathode sealing strip together can improve the sealing effect in the metal bipolar plate and prevent gas leakage.

[0083] Therefore, the installation of anode and cathode sealing strips eliminates the need for gaskets used in traditional semi-enclosed cathode air-cooled fuel cell bipolar plates, avoiding the problems of insufficient sealing margin, sensitivity to clamping force distribution, and susceptibility to local failures associated with traditional gaskets.

[0084] This application also provides a semi-enclosed cathode air-cooled fuel cell stack, such as Figure 9 As shown, the semi-enclosed cathode air-cooled fuel cell stack 13 includes at least an upper end plate 4, an upper insulating plate 5, an upper current collector 6, a core 7, a lower current collector 8, a lower insulating plate 9, and a lower end plate 10. The core 7 comprises, from top to bottom, a metal bipolar plate, a membrane electrode assembly 11, and a support mesh 12, stacked periodically, ending with a metal bipolar plate. Here, the metal bipolar plate is only present in… Figure 10 In Chinese, it is represented by BPP.

[0085] This application also provides a semi-closed cathode air-cooled fuel cell system, such as Figure 11 As shown, the battery system includes at least one of the aforementioned semi-enclosed cathode air-cooled fuel cell stacks 13, and also includes a fuel gas supply subsystem, a thermal management system, and an electronic control unit, wherein: The fuel gas supply subsystem includes a blower 14, a fuel gas circulation pump 15, a fuel gas injector 16, and an exhaust valve 17 applied to a semi-enclosed cathode air-cooled fuel cell metal bipolar plate as described above. The cathode reaction air of the cathode plate 3 in the metal bipolar plate is supplied by the blower 14, and the pressure range of the blower is 0-30 kPa. The anode fuel gas of the anode plate 1 in the metal bipolar plate is supplied by the fuel gas circulation pump 15, the fuel gas injector 16, and the exhaust valve 17.

[0086] The thermal management system includes at least a cooling fan 18, and the cooling gas for the cooling plate 2 in the metal bipolar plate is supplied by the cooling fan 18.

[0087] The electronic control unit includes at least a DC-DC converter 19.

[0088] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A semi-enclosed cathode air-cooled fuel cell metal bipolar plate, comprising an anode plate, a cooling plate, and a cathode plate, characterized in that: The active regions of the cathode plate, cooling plate, and anode plate are stacked to form the active region of the metal bipolar plate. The active region of the metal bipolar plate is divided into a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side. The low current density and medium voltage drop region on the inlet side, the medium current density and low voltage drop region in the middle, and the high current density and high voltage drop region on the outlet side are all square. The low current density and medium voltage drop region on the inlet side is located in the lower part of the active region of the metal bipolar plate, the medium current density and low voltage drop region in the middle is located in the middle of the active region of the metal bipolar plate, and the high current density and high voltage drop region on the outlet side is located in the upper part of the active region of the metal bipolar plate. The active region based on the metal bipolar plate is divided into a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side. The corresponding positions on the cathode plate, cooling plate, and anode plate are also divided into a low current density and medium voltage drop region on the inlet side, a medium current density and low voltage drop region in the middle, and a high current density and high voltage drop region on the outlet side. An anode gas inlet is provided on one side of the low current density and medium voltage drop region on the inlet side, and an anode gas outlet is provided on one side of the high current density and high voltage drop region on the outlet side. The length and width of the active region of the metal bipolar plate are determined according to the following model: ； In the formula: The width of the active region of the metal bipolar plate; The width of the low current density, medium voltage drop region on the inlet side; The width of the low voltage drop region with medium current density in the middle section; The width of the high current density high voltage drop zone on the export side; is the length of the active region of the metal bipolar plate; The length of the voltage drop region at low current density on the inlet side. The length of the medium current density, low voltage drop region in the middle section. The length of the high current density and high voltage drop zone on the export side; For the anode flow channel cycle; This refers to the number of anode flow channels; The region of the voltage drop zone in the low current density at the inlet side is determined according to the following model: ； In the formula: is the length of the active region of the metal bipolar plate; The width of the active region of the metal bipolar plate; For the anode flow channel cycle; The number of anode flow channels; where and The configuration is based on a three-dimensional coordinate system, with the plane where the anode plate is located configured as the XOY plane, and the direction perpendicular to the anode plate as the Z axis; The region of low current density and low voltage drop in the central part is determined according to the following model: ； in, is the length of the active region of the metal bipolar plate; is the anode flow channel period; is the number of anode flow channel elements. The region of the high current density and high voltage drop zone on the outlet side is determined according to the following model: ； in, is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; This represents the number of anode flow channels.

2. The semi-enclosed cathode air-cooled fuel cell metal bipolar plate according to claim 1, characterized in that: In the low current density and low voltage drop region at the inlet side, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; In the central region with low current density and low voltage drop, several cathode channels are configured to cause the cathode reactant gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to tend to flow in the positive X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; In the high current density and high voltage drop region on the outlet side, several cathode channels are configured to cause the cathode reactive gas to tend to flow in the positive X-axis direction, and the centerline of the cathode channels is... The projection onto the XOY plane forms an angle with the X-axis. , Several anode channels are configured to cause the anode fuel gas to flow in the negative X-axis direction, and the centerline of the anode channels is... The projection onto the XOY plane forms an angle with the X-axis. , ; Several cooling channels are configured in the low current density and medium pressure drop region at the inlet, the medium current density and low pressure drop region in the middle, and the high current density and high pressure drop region at the outlet to encourage the cooling gas to flow in the positive Y-axis direction, and the centerline of the cooling channels is... The projection onto the XOY plane forms an angle with the X-axis. , .

3. The semi-enclosed cathode air-cooled fuel cell metal bipolar plate according to claim 2, characterized in that: The centerlines of each flow channel in the low current density and medium voltage drop region on the inlet side, the medium current density and low voltage drop region in the middle, and the high current density and high voltage drop region on the outlet side are determined according to the following model: ； In the formula: For the first The centerline of the direct current path of the root cathode; Centerline of the cathode flow channel The projection onto the XOY plane forms an angle with the X-axis; The width of the active region of the metal bipolar plate; For the cathode flow channel period; For the first The centerline of the root anode flow channel; Centerline of the anode flow channel The projection onto the XOY plane forms an angle with the X-axis; is the length of the active region of the metal bipolar plate; For the anode flow channel cycle; For the first The centerline of the root cooling channel; Centerline of the cooling channel The projection onto the XOY plane forms an angle with the X-axis; This is the cooling channel cycle.

4. The semi-enclosed cathode air-cooled fuel cell metal bipolar plate according to claim 3, characterized in that: A fuel gas diversion transition structure is provided between the low current density and medium pressure drop zone at the inlet side of the anode plate and the medium current density and low pressure drop zone in the middle, so that the flow direction of the anode fuel gas changes from a tendency to flow in the negative X-axis direction to a tendency to flow in the positive X-axis direction; and a similar fuel gas diversion transition structure is provided between the medium current density and low pressure drop zone in the middle of the anode plate and the high current density and high pressure drop zone at the outlet side, so that the flow direction of the anode fuel gas changes from a tendency to flow in the positive X-axis direction to a tendency to flow in the negative X-axis direction. The parameters of the fuel gas diversion transition structure include the anode flow channel width. inner corner radius outer corner radius And satisfy: .

5. A semi-enclosed cathode air-cooled fuel cell metal bipolar plate according to claim 4, characterized in that: The metal bipolar plate also includes an anode sealing strip for the anode plate and a cathode sealing strip for the cathode plate. The anode sealing strip seals the anode flow channels on the anode plate, and the cathode sealing strip seals the cathode flow channels and cooling flow channels on the cathode plate and cooling plate. The height of the anode sealing strip is [missing information]. The thickness of the cathode sealing strip is The anode sealing groove and the cathode sealing groove are respectively formed by folding the plate matrix of the anode plate and the plate matrix of the cathode plate, and are used to accommodate the anode sealing strip and the cathode sealing strip respectively, and their depths are both... , And satisfy: ； ； In the formula: This refers to the thickness of the substrate material for the anode and cathode plates. ; For cooling channel depth, ; The compression factor is 1. .

6. A semi-enclosed cathode air-cooled fuel cell metal bipolar plate according to claim 5, characterized in that: Set the centerline of the cathode flow channel The projection of the centerline of the anode flow channel onto the XOY plane forms an angle. The centerline of the cathode flow channel Centerline of the cooling channel The projection on the XOY plane forms an angle. ,but: The included angle within the low current density and medium voltage drop region on the inlet side Angle and cathode flow channel period Anode flow channel cycle If it is a variable, then the included angle satisfy included angle satisfy Cathode flow channel period satisfy Cathode flow channel period satisfy And satisfy: ； ； Therefore, the current density in the low current density and voltage drop region at the inlet side is determined by the following model: ； The cathode voltage drop in the low current density region at the inlet side is determined according to the following model: ； The current density in the middle region with low current density and low voltage drop is determined according to the following model: ； The cathode voltage drop in the medium current density, low voltage drop region of the central part is determined according to the following model: ； The current density in the high current density and high voltage drop zone on the outlet side is determined according to the following model: ； The cathode voltage drop in the high current density and high voltage drop zone on the outlet side is determined according to the following model: 。 7. A semi-enclosed cathode air-cooled fuel cell stack, comprising end plates, insulating plates, current collectors, and a stack core, characterized in that: The core includes a semi-enclosed cathode air-cooled fuel cell metal bipolar plate as described in any one of claims 1 to 6. The core consists of metal bipolar plates and membrane electrode assemblies stacked sequentially from top to bottom, ending with a metal bipolar plate.

8. A semi-hermetic cathode air-cooled fuel cell system, characterized in that: The battery system includes a blower and a semi-enclosed cathode air-cooled fuel cell stack as described in claim 7, wherein the pressure range of the blower is 0-30 kPa.

9. A design method for a semi-closed cathode air-cooled fuel cell, characterized in that: The design method, applied to a semi-enclosed cathode single cell comprising a semi-enclosed cathode air-cooled fuel cell metal bipolar plate as described in any one of claims 1 to 6, specifically includes: S1. Determine the optimization objective for a semi-enclosed cathode single cell. Design variables and design variable constraints, where p is the optimization objective index symbol, and optimization objective g1 is the total current density. I The optimization objective g2 is the total cathode voltage drop. Pa ; l To design variable index symbols, design variables. x 1 represents the cathode flow channel period. Design variables x 2 represents the anode flow channel cycle. Design variables x 3 is the centerline of the cathode flow channel. With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane Design variables x 4 is the centerline of the cathode flow channel. With the centerline of the cooling channel The included angle formed by the projection on the XOY plane The design variable constraints are: ,in and For the first l Upper and lower limits of a design variable; S2. Based on the initial settings in step S1, design multiple experimental schemes, and fit the performance values ​​of each optimization objective of the semi-enclosed cathode single cell to establish a second-order polynomial objective function for each optimization objective of the semi-enclosed cathode single cell. The second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell. As shown in the following formula: ； The second-order polynomial objective function of the optimization objective g2 of a semi-enclosed cathode single cell. As shown in the following formula: ； The second-order polynomial objective function of the optimization objective g1 of the semi-enclosed cathode single cell is... for: ； In the formula, The constant term coefficient of the total current density, Total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient, For the total current density Term coefficient; The second-order polynomial objective function of the optimization objective g2 of a semi-enclosed cathode single cell. for: ； In the formula, The constant term coefficient for the total cathode voltage drop is... Total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For the total cathode voltage drop Term coefficient, For cathode voltage drop Term coefficient; S3. Optimization Objectives Based on Semi-Enclosed Cathode Single Cells Second-order polynomial objective function Design variables for semi-enclosed cathode single cells: cathode flow channel period x 1 Anode flow channel cycle x 2 Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3 Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4 Classify the strategies to obtain a set of combinations; S4. Determine the design variables for the pre-optimized semi-enclosed cathode single cell: cathode flow channel period. x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x The value of 4 is determined, and the initial strategy set for each optimization objective of the semi-enclosed cathode single cell is determined based on the strategy set combination obtained in step S3. and complement ; S5, the total current density of a semi-enclosed cathode single cell. g 1. Total cathode voltage drop g 2. To optimize the objectives, a multi-objective benefit model for a semi-enclosed cathode single cell is established. The combined weighting method is used to calculate the combined weight coefficients of each optimization objective in the multi-objective benefit model for the semi-enclosed cathode single cell. The benefit functions of each optimization objective for the semi-enclosed cathode single cell are shown in the following equation: ； In the formula: For the semi-enclosed cathode single cell p The optimal strategy set for each optimization objective; For the semi-enclosed cathode single cell p An initial policy set for each optimization objective; For the semi-enclosed cathode single cell p The complement of each optimization objective; For the semi-enclosed cathode single cell p A second-order polynomial objective function with optimization objectives; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; In a semi-enclosed cathode single cell, except for the first p The second-order polynomial objective function for all optimization objectives other than the first optimization objective; In a semi-enclosed cathode single cell, except for the first p The combined weight coefficients of the remaining optimization objectives besides the first optimization objective; The combined weighting method first calculates the subjective weight coefficients of each optimization objective using the analytic hierarchy process (AHP), then calculates the objective weight coefficients using the entropy weighting method, and finally calculates the combined weight coefficients of each optimization objective in the multi-objective benefit model of a semi-closed cathode single cell. The formula for the combined weighting method is shown below: ； In the formula: This indicates the semi-enclosed cathode single cell. p The subjective weight coefficients of each optimization objective; This indicates the semi-enclosed cathode single cell. p Objective weighting coefficients for each optimization objective; S6. After optimizing the reward function of each optimization objective of the semi-enclosed cathode single cell using an optimization algorithm, the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell is obtained. And the optimal strategy set for each optimization objective of the semi-enclosed cathode single cell. The combined cathode flow channel period is obtained for a semi-enclosed cathode single cell. x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4. Optimal combination of design variables ; S7. Based on the optimal design variable set combination obtained for the semi-enclosed cathode single cell. Design a semi-enclosed cathode single cell and obtain the optimization objectives for the optimized semi-enclosed cathode single cell: total current density. g 1. Total cathode voltage drop g The performance values ​​of the 2-cell semi-enclosed cathode single cell were evaluated, and a comprehensive score was given for the semi-enclosed cathode single cell before and after optimization. The comprehensive performance score of the semi-enclosed cathode single cell before optimization was obtained. And the comprehensive performance score of the optimized semi-enclosed cathode single cell The scoring formula is shown below: ； In the formula: S represents the overall performance score; For the semi-enclosed cathode single cell p The combined weighting coefficients of the optimization objectives; The first semi-enclosed cathode single cell after normalization treatment p Performance values ​​of each optimization objective; S8. Compare and optimize the overall performance scores of the semi-enclosed cathode single cell before and after optimization. Then return to step S4 and use the optimal design variable set combination for the semi-enclosed cathode single cell. Replace the original design variable values ​​of the semi-enclosed cathode single cell with the current design variable values, and redesign accordingly; if The optimization ends when the optimal combination of design variables for the semi-enclosed cathode single cell is output. Middle cathode flow channel period x 1. Anode flow channel cycle x 2. Cathode flow channel centerline With the centerline of the anode flow channel The included angle formed by the projection on the XOY plane x 3. Cathode flow channel centerline With the centerline of the cooling channel The included angle formed by the projection on the XOY plane x 4. Values ​​of each design variable.

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