High-precision hydraulic radius design method for gas flow channel of bipolar plate of fuel cell

Abstract

The present application discloses a high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method, comprising: measuring the elastic modulus E, Poisson's ratio ε and stress-strain curve of the bipolar plate and the gas diffusion layer; analyzing and calculating the compression deformation and displacement of the bipolar plate and the gas diffusion layer under a predetermined assembly pressure and service condition; calculating the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel according to the compression deformation and displacement generated by the bipolar plate and the gas diffusion layer; calculating the hydraulic radius R of the gas flow channel under the assembly pressure and service condition according to the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel, wherein R=A / L; determining the difference between the actual value of the hydraulic radius of the reaction gas flow channel and the design target value, and adjusting any one or more of the groove depth, groove width and draft angle parameters of the bipolar plate to make the actual value of the hydraulic radius of the reaction gas flow channel consistent with the design target value.

Description

Technical Field

[0001] The present application relates to the field of fuel cells, and in particular to a method for calculating the hydraulic radius of a gas flow channel of a bipolar plate of a fuel cell with high precision. Background Art

[0002] Proton exchange membrane fuel cells have the characteristics of high power generation efficiency, low operating temperature, fast startup rate and green environmental protection. They have broad application prospects in aerospace, portable power generation and transportation.

[0003] Proton exchange membrane fuel cells are mainly composed of bipolar plates, gas diffusion layers, catalyst layers and proton exchange membranes. Among them, the bipolar plate, as one of the key parts of proton exchange membrane fuel cells, has a very important influence on the distribution of reaction gases, current collection and conduction, and water and heat management. In the process of proton exchange membrane fuel cell structure and performance design, it is usually necessary to determine the hydraulic radius of the reaction gas flow channel in the bipolar plate of the fuel cell, so as to optimize the transmission, distribution and gas pressure difference of the reaction gas inside the bipolar plate flow channel, increase the discharge capacity of the product water, and thus improve the performance and reliability of the fuel cell. However, during the assembly and service of the proton exchange membrane fuel cell, the hydraulic radius of the reaction gas flow channel section will change with the assembly pressure and operating conditions, resulting in inconsistency with the initial design value. The hydraulic radius of the reaction gas flow channel of the proton exchange membrane fuel cell refers to the ratio of the cross-sectional area of ​​the reaction gas flow channel to the wetted perimeter, that is, hydraulic radius (R) = reaction gas flow channel cross-sectional area (A) / wetted perimeter (L). Therefore, accurately calculating the changes in the cross-sectional area of ​​the bipolar plate reaction gas flow channel during assembly and service plays a very important role in optimizing the bipolar plate flow channel structural parameters and the hydraulic radius of the gas flow channel, improving the power generation efficiency and reliability of proton exchange membrane fuel cells, and reducing the overall energy consumption of the fuel cell system.

[0004] Due to the small structure of the flow channel and the relatively complex structure of the flow channel of the commonly used metal bipolar plate, it is generally difficult to directly measure the hydraulic radius of the reaction gas flow channel with a measuring instrument. At present, in the design process of bipolar plates and fuel cells, the hydraulic radius of the reaction gas flow channel usually uses an estimated value or empirical value before assembly, so it is impossible to obtain the accurate value of the hydraulic radius of the reaction gas flow channel during actual assembly and service.

[0005] At the same time, the impact of changes in the hydraulic radius of the reaction gas flow channel on the performance and reliability of the fuel cell cannot be quantitatively analyzed, making it impossible to achieve precise design of the reaction gas flow channel of the proton exchange membrane fuel cell bipolar plate, limiting the improvement of the power generation efficiency and reliability of the proton exchange membrane fuel cell and the reduction of its cost. Summary of the invention

[0006] In view of the problems of the prior art, the present invention provides a high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method, so as to achieve accurate design of the proton exchange membrane fuel cell bipolar plate reaction gas flow channel and improve the power generation efficiency and reliability of the proton exchange membrane fuel cell.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] A high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method, comprising:

[0009] Measure the elastic modulus E and Poisson’s ratio ν of the bipolar plate and gas diffusion layer;

[0010] Analyze and calculate the compression deformation and displacement of the bipolar plate and gas diffusion layer under the predetermined assembly pressure and service conditions;

[0011] According to the compression deformation and displacement of the bipolar plate and the gas diffusion layer, the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel are calculated;

[0012] According to the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel, the hydraulic radius R and the equivalent diameter De of the gas flow channel under the assembly pressure and service conditions are calculated; wherein R = A / L; De = K·A / L; K value is 4;

[0013] The difference between the actual value of the hydraulic radius of the reaction gas flow channel and the design target value is determined, and the actual value of the hydraulic radius of the reaction gas flow channel is made consistent with the design target value by adjusting the bipolar plate structural parameters.

[0014] Preferably, in the step of compressing the deformation and displacement of the bipolar plate and the gas diffusion layer, a solid mechanics module, a multi-physics field coupling module and a steady-state calculation method are used to directly calculate the compressive deformation and displacement of the bipolar plate and the gas diffusion layer under a predetermined assembly pressure and service conditions.

[0015] Preferably, the step of analyzing and calculating the compression deformation and displacement of the bipolar plate and the gas diffusion layer is performed as follows:

[0016] According to the physical equation shown in the following formula, the constitutive relationship of the calculation object is defined in MATLAB software:

[0017] S–(S0+S t )=C:(ε–(ε0+ε t +ε s )

[0018] Among them, S is stress, S0 is prestress, S t is the external stress, C is the elastic matrix, ε is the elastic strain, ε0 is the prestrain, ε t is the thermal strain, ε sis the expansion strain; all units are international units;

[0019] According to the geometric equation shown in the following formula, the deformation coordination relationship of the calculation object is defined in MATLAB software:

[0020]

[0021] in, is the total strain, is the displacement gradient, is the tangential displacement gradient;

[0022] According to the constitutive relationship and the deformation coordination relationship, the compression deformation and displacement of the bipolar plate and the gas diffusion layer under the predetermined assembly pressure and service conditions are obtained.

[0023] Preferably, the step of calculating the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel is performed as follows:

[0024] The MATLAB software is used to directly calculate the results and generate the compression deformation and displacement diagrams of the bipolar plate and gas diffusion layer;

[0025] Using the edge function in MATLAB software, the cross-sectional profile of the gas flow channel surrounded by the bipolar plate and the gas diffusion layer after the compression deformation is extracted according to the compression deformation and displacement diagram;

[0026] The regionprops function in MATLAB software is used to calculate the actual cross-sectional area A and wetted perimeter L of the gas flow channel after compression deformation based on the extracted cross-sectional profile.

[0027] Preferably, the bipolar plate material is selected from one of stainless steel, titanium and its alloys, aluminum and its alloys, or copper and its alloys; the thickness of the bipolar plate substrate is 50 μm to 200 μm.

[0028] Preferably, the gas diffusion layer is made of carbon paper or carbon cloth; the thickness of the gas diffusion layer is 100 μm to 500 μm.

[0029] Preferably, the bipolar plate structural parameters include groove depth (h), groove width (W c ), ridge width (W r ), any one or more of the draft angle (α), ridge radius (R), and groove radius (r).

[0030] Preferably, the assembly pressure ranges from 0 MPa to 2.5 MPa.

[0031] Preferably, the service conditions are: operating temperature of -30°C to 90°C, reaction gas pressure of 30 to 100 bar, and relative humidity of 30% to 90%.

[0032] Beneficial effects:

[0033] (1) The present invention uses mathematical calculation and analysis methods to accurately calculate the cross-sectional area, wetted perimeter and hydraulic radius of the microscopic reaction gas flow channel of the proton exchange membrane fuel cell bipolar plate;

[0034] (2) The present invention provides data support for the design of metal bipolar plate flow channel structure parameters and proton exchange membrane fuel cell design through hydraulic radius calculation, thereby achieving accurate and efficient design before manufacturing.

[0035] (3) The present invention can provide accurate basic data for the analysis and calculation of mass transfer, heat transfer, electrical conductivity and drainage performance in proton exchange membrane fuel cells, thereby facilitating the manufacture of high-efficiency, high-reliability and low-cost fuel cell stacks and systems.

[0036] With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

[0037] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0038] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of 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 paying any creative labor.

[0040] Figure 1 Schematic diagram of the cross-sectional structure of the gas flow channel of the proton exchange membrane fuel cell of the present invention, wherein (a) is the cross-sectional structure of the reaction gas flow channel without considering the assembly and actual service conditions; (b) is the cross-sectional structure of the reaction gas flow channel under the actual assembly and service conditions;

[0041] Figure 2 It is a specific implementation flow chart of the method for accurately calculating and designing the hydraulic radius of the reaction gas flow channel of the bipolar plate of the proton exchange membrane fuel cell of the present invention;

[0042] Figure 3is a stress-strain curve diagram of SGL 28BC carbon paper of Example 1;

[0043] Figure 4 1 is a compression deformation and displacement diagram of SS316L stainless steel bipolar plate and SGL 28BC carbon paper when the assembly pressure of Example 1 is 0.5 MPa;

[0044] Figure 5 1 is a diagram of compression deformation and displacement of SS316L stainless steel bipolar plate and SGL 28BC carbon paper when the assembly pressure of Example 1 is 1.0 MPa;

[0045] Figure 6 1 is a diagram of compression deformation and displacement of SS316L stainless steel bipolar plate and SGL 28BC carbon paper when the assembly pressure of Example 1 is 1.5 MPa. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0049] An embodiment of the present invention provides a method for accurately calculating and designing the microstructure dimensions during the assembly and service of a proton exchange membrane fuel cell, specifically a method for accurately calculating and designing the hydraulic radius of a fuel cell reaction gas flow channel.

[0050] As attached Figure 1As shown in the figure, the dotted area enclosed by the bipolar plate and the gas diffusion layer is the reaction gas flow channel section A, and the total perimeter of the enclosed dotted area is: wetted perimeter L. The reaction gas flow channel section without considering the assembly and service process is shown in the attached figure. Figure 1 (a) shows the cross section of the reaction gas flow channel considering the actual assembly and service conditions. Figure 1 (b) as shown.

[0051] In the process of designing the cross-section of the reaction gas flow channel of the conventional proton exchange membrane fuel cell, the stamping fillet of the bipolar plate is generally ignored and simplified into a trapezoid for estimation or directly using empirical values. The precise calculation and design method of the hydraulic radius of the reaction gas flow channel of the bipolar plate of the proton exchange membrane fuel cell in this embodiment is shown in the attached specific implementation process. Figure 2 As shown, the following steps are included:

[0052] (1) Using a high-precision universal tensile testing machine, accurately measure the elastic modulus (E), Poisson's ratio (ν) and stress-strain curve of the bipolar plate and the gas diffusion layer; for linear elastic materials (such as the bipolar plate in this embodiment), the elastic modulus E and Poisson's ratio ν can be directly calculated based on the tensile curve; for nonlinear elastic materials (such as the gas diffusion layer in this embodiment), the elastic modulus E and Poisson's ratio ν are given by the stress-strain curve in the tensile curve;

[0053] (2) Analyze and calculate the compression deformation and displacement of the bipolar plate and the gas diffusion layer under specific assembly pressure and service conditions by using any one or more commercial simulation analysis software such as ABAQUS, ANSYS and COMSOL, or by using MATLAB commercial mathematical software to compile a program;

[0054] This step (2) is specifically implemented as the following sub-steps:

[0055] ①. Choose one of the commercial simulation software such as ANSYS, ABAQUS or COMSOL, or MATLAB commercial mathematical software;

[0056] ② If one of the commercial simulation software such as ANSYS, ABAQUS or COMSOL is selected, the solid mechanics module, multi-physics coupling module and steady-state calculation method are used to directly calculate the compression deformation and displacement of the bipolar plate and gas diffusion layer under the predetermined assembly pressure and service conditions;

[0057] ③. If MATLAB commercial mathematical software is selected, the analysis and calculation process is as follows:

[0058] (a) First, define the constitutive relationship of the calculation object in MATLAB software according to the physical equation shown in formula (1);

[0059] S – (S0 + S t) = C:(ε – (ε0 + ε t + ε s ) (1)

[0060] Among them, S is stress, S0 is prestress, S t is the external stress, C is the elastic matrix, ε is the elastic strain, ε0 is the prestrain, ε t is the thermal strain, ε s is the expansion strain.

[0061] (b) Based on the geometric equation shown in formula (2), the deformation coordination relationship of the calculation object is defined in MATLAB software;

[0062]

[0063] in, is the total strain, is the displacement gradient, is the tangential displacement gradient;

[0064] (c) According to the program written in MATLAB software, the compression deformation and displacement of the bipolar plate and gas diffusion layer under the predetermined assembly pressure and service conditions are calculated.

[0065] Among them, Poisson's ratio ν is used to determine the strain perpendicular to the compression direction, and the calculation formula is ε x =-νε z , where ε x is the compressive strain, ε z is the strain in the vertical compression direction, which is included in the elastic matrix C. The elastic modulus E is brought into the stress-strain formula in the constitutive relationship for calculation, and is included in the elastic matrix C to determine the strain under the assembly stress; thus, the elastic modulus E and Poisson's ratio ν are both included in the elastic matrix C, and C is used to describe this embodiment.

[0066] (3) According to the compression deformation and displacement of the bipolar plate and the gas diffusion layer under specific assembly pressure and service conditions, the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel are calculated using MATLAB commercial mathematical software;

[0067] This step (3) includes the following sub-steps:

[0068] S31, exporting the compression deformation and displacement diagrams of the bipolar plate and the gas diffusion layer from commercial simulation software such as ANSYS, ABAQUS and COMSOL, and then importing them into MATLAB software, or directly generating compression deformation and displacement cloud diagrams based on the calculation results of MATLAB software;

[0069] S32, using the edge function in MATLAB software to extract the cross-sectional profile of the gas flow channel surrounded by the bipolar plate and the gas diffusion layer after compression deformation;

[0070] S33. Use the regionprops function in MATLAB software to calculate the actual cross-sectional area A and wetted perimeter L of the gas flow channel after compression deformation.

[0071] (4) According to the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel, the hydraulic radius R (R = A / L) of the gas flow channel under the assembly pressure and service conditions is calculated; the equivalent diameter De of the gas flow channel, De = K·A / L; the K value is 4;

[0072] (5) Determine the difference between the actual value of the hydraulic radius of the reaction gas flow channel and the design target value, and make the actual value of the hydraulic radius of the reaction gas flow channel consistent with the design target value by adjusting any one or more of the parameters such as the groove depth, groove width, and draft angle.

[0073] In this embodiment, it is assumed that the hydraulic radius of the flow channel when not deformed is the target design value. The hydraulic radius after reduction is determined based on the cross-sectional area A and the wetted perimeter L after compression, and then it is determined that the bipolar plate groove depth needs to be increased by 0.01 mm. The design target value refers to the "hydraulic radius" of the flow channel, and the bipolar plate groove depth is one of its structural parameters. The change of its hydraulic radius is mainly achieved by adjusting the groove depth.

[0074] The present invention is described in detail below using specific embodiments to facilitate a better understanding of the present invention.

[0075] Example 1

[0076] This embodiment provides a high-precision calculation and design method for the hydraulic radius of gas flow of a fuel cell bipolar plate, as follows:

[0077] (1) The bipolar plate material is 0.1 mm thick SS316L stainless steel sheet, and the gas diffusion layer is 0.2 mm thick SGL28BC carbon paper. The mechanical properties of SS316L stainless steel and SGL 28BC carbon paper were tested using a high-precision tensile testing machine. The results are shown in Table 1:

[0078] Table 1 Mechanical properties of SS316L stainless steel and SGL 28BC carbon paper

[0079] name Elastic modulus / GPa Poisson's ratio <![CDATA[Density / kg / m 3 > SS316L stainless steel bipolar plate 205 0.28 8000 SGL 28BC Carbon Paper E(ε) 0.01 440

[0080] Among them, E(ε) is obtained by adding Figure 3 The stress-strain curve shown is expressed in the form of a stress-strain curve.

[0081] (2) The commercial simulation analysis software COMSOL (MATLAB commercial mathematical software) was used to calculate the compression deformation and displacement of SS316L stainless steel bipolar plates and SGL 28BC carbon paper when the assembly pressures were 0.5 MPa, 1.0 MPa, and 1.5 MPa, respectively. The results are shown in the attached figure. Figure 4-6 The initial design dimensions of the bipolar plate are: groove depth 0.5 mm, groove width 1.0 mm, ridge width 1.4 mm, draft angle 22°, ridge radius 0.5 mm, and groove radius 0.15 mm.

[0082] (3) Using MATLAB commercial mathematical software (hereinafter referred to as "MATLAB software"), the actual cross-sectional area A and wetted perimeter L of the reaction gas flow channel are calculated to be 0.65 mm when the assembly pressure is 0.5 MPa. 2 and 3.70mm, such as Figure 4 As shown; when the calculated assembly pressure is 1.0MPa, the actual cross-sectional area A and wetted perimeter L of the reaction gas flow channel are 0.63mm 2 and 3.62mm, such as Figure 5 As shown; when the calculated assembly pressure is 1.5MPa, the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel are 0.61mm 2 and 3.57mm, such as Figure 6 shown.

[0083] (4) According to the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel under different assembly pressures, it is calculated that when the assembly pressure is 0.5 MPa, the hydraulic radius of the reaction gas flow channel is 0.175 mm; when the assembly pressure is 1.0 MPa, the hydraulic radius of the reaction gas flow channel is 0.173 mm; when the assembly pressure is 1.5 MPa, the hydraulic radius of the reaction gas flow channel is 0.170 mm.

[0084] (5) According to the difference between the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel under different assembly pressures and the target design values, it is determined that when the assembly pressure is 0.5 MPa, the design value of the bipolar plate groove depth needs to be increased by 0.01 mm on the basis of no deformation; when the assembly pressure is 1.0 MPa, the design value of the bipolar plate groove depth needs to be increased by 0.03 mm on the basis of no deformation; when the assembly pressure is 1.5 MPa, the design value of the bipolar plate groove depth needs to be increased by 0.05 mm on the basis of no deformation.

[0085] Any numerical value cited herein includes all values ​​of lower and upper values ​​that increase by one unit from the lower limit to the upper limit, and there is at least a two-unit interval between any lower value and any higher value. For example, if the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is stated to be from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in the specification. For values ​​less than 1, one unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be clearly expressed, and it can be considered that all possible combinations of numerical values ​​listed between the lowest value and the highest value are clearly stated in the specification in a similar manner.

[0086] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", including at least the specified endpoints.

[0087] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The term "consisting essentially of..." to describe a combination should include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to indicate that any attribute described that "may" include is optional.

[0088] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0089] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents possessed by such claims. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the inventors did not consider the subject matter to be part of the disclosed inventive subject matter.

Claims

1. A high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method, comprising: Measure the elastic modulus E and Poisson’s ratio ν of the bipolar plate and gas diffusion layer; Analyze and calculate the compression deformation and displacement of the bipolar plate and gas diffusion layer under the predetermined assembly pressure and service conditions; According to the compression deformation and displacement of the bipolar plate and the gas diffusion layer, the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel are calculated; According to the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel, the hydraulic radius R and the equivalent diameter De of the gas flow channel under the assembly pressure and service conditions are calculated; where R = A / L; De = K·A / L; K value is 4; Determine the difference between the actual value of the hydraulic radius of the reaction gas flow channel and the design target value, and adjust the bipolar plate structural parameters so that the actual value of the hydraulic radius of the reaction gas flow channel is consistent with the design target value; The steps of analyzing and calculating the compression deformation and displacement of the bipolar plate and the gas diffusion layer are performed as follows: According to the physical equation shown in the following formula, the constitutive relationship of the calculation object is defined in MATLAB software: S – (S0 + S t ) = C:(ε – (ε0 + ε t + e s ) Where S is stress, S 0 For prestressing, S t is the external stress, C is the elasticity matrix, ε is the elastic strain, ε 0 is the prestrain, ε t is the thermal strain, ε s is the expansion strain; all units are international units; According to the geometric equation shown in the following formula, the deformation coordination relationship of the calculation object is defined in MATLAB software: in, is the total strain, is the displacement gradient, is the tangential displacement gradient; According to the constitutive relationship and the deformation coordination relationship, the compression deformation and displacement of the bipolar plate and the gas diffusion layer under the predetermined assembly pressure and service conditions are obtained.

2. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: In the step of compressing the deformation and displacement of the bipolar plate and the gas diffusion layer, a solid mechanics module, a multi-physics field coupling module and a steady-state calculation method are used to directly calculate the compressive deformation and displacement of the bipolar plate and the gas diffusion layer under a predetermined assembly pressure and service conditions.

3. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The step of calculating the actual cross-sectional area A and the wetted perimeter L of the reaction gas flow channel is performed as follows: The MATLAB software is used to directly calculate the results and generate the compression deformation and displacement diagrams of the bipolar plate and gas diffusion layer; Using the edge function in MATLAB software, the cross-sectional profile of the gas flow channel surrounded by the bipolar plate and the gas diffusion layer after the compression deformation is extracted according to the compression deformation and displacement diagram; The regionprops function in MATLAB software is used to calculate the actual cross-sectional area A and wetted perimeter L of the gas flow channel after compression deformation based on the extracted cross-sectional profile.

4. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The bipolar plate material is selected from one of stainless steel, titanium and its alloys, aluminum and its alloys, or copper and its alloys.

5. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The gas diffusion layer is made of carbon paper or carbon cloth; the thickness of the gas diffusion layer is 100 μm to 500 μm.

6. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The bipolar plate structural parameters include any one or more of groove depth, groove width, ridge width, draft angle, ridge fillet, and groove fillet.

7. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The assembly pressure range is: 0 MPa ~ 2.5 MPa.

8. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: Service conditions: operating temperature -30 ℃ ~ 90 ℃, reaction gas pressure 30 ~ 100 bar, relative humidity 30% ~90%.

9. The high-precision fuel cell bipolar plate gas flow channel hydraulic radius design method according to claim 1, wherein: The thickness of the bipolar plate substrate is 50 μm to 200 μm.

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