A method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate

Abstract

The present invention discloses a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, belonging to the technical field of fuel cells. The present invention establishes a full-size SOFC electrode plate finite element model and simulates the electrode plate preparation process to obtain the residual stress distribution field of the electrode plate; a full-size SOFC stack unit finite element model is also established, and based on the obtained residual stress distribution field of the electrode plate, a cyclic thermal temperature field is applied for numerical simulation to obtain the evolution law of the thermal stress of the electrode plate in the start-stop cycle condition in the stack unit; at the same time, an electrode plate thermal fatigue damage prediction model is constructed, and using the obtained evolution law of the thermal stress of the electrode plate, the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles is calculated to predict the thermal fatigue life of the electrode plate. The present invention realizes the prediction of the thermal fatigue life of the electrode plate, and can provide a theoretical reference for the design of the stack and preventive maintenance during the operation process to ensure its long-term stable operation.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and particularly relates to a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate. Background Art

[0002] Solid Oxide Fuel Cell (SOFC for short) belongs to the third generation of fuel cells. This all-solid-state chemical power generation device can directly convert the chemical energy in fuel and oxidant into electrical energy under medium and high temperature (600 - 1000 °C) conditions, and has the advantages of high energy conversion efficiency, low cost, high specific power, wide fuel sources, environmental friendliness, etc. It is widely used in mobile power, combined heat and power, distributed power, transportation and military fields. However, at present, SOFC has not been fully commercialized, and one of the main reasons is the limitation of the high-temperature strength of SOFC, especially its electrode plate structure. The SOFC electrode plate is also called PEN plate (Positive-Electrolyte-Negative), which is composed of various ceramic materials, and its thermal properties vary significantly. During both the preparation and service processes, thermal stress is inevitably generated. Especially when the SOFC stack needs to be frequently started and stopped due to maintenance or working requirements, thermal fatigue failure is extremely likely to occur. The fatigue cracking of the PEN plate will not only seriously affect the operating performance of the entire stack, but once it cracks and causes fuel gas leakage inside the battery, it will cause a greater safety accident. Therefore, how to predict the thermal fatigue life of SOFC is the key issue to ensure the long-term stable operation of the SOFC stack. Summary of the Invention

[0003] To solve the above technical problems, the present invention proposes a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate.

[0004] The present invention specifically adopts the following technical solutions:

[0005] The present invention provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, including the steps of:

[0006] S1. According to the material compositions of the structures of each unit of the SOFC stack, prepare test specimens of each material and obtain the relevant parameters of each material;

[0007] S2. Establish a full-scale finite element model of the SOFC electrode plate, simulate the preparation process of the electrode plate, and obtain the residual stress distribution field of the electrode plate;

[0008] S3. Establish a full-scale finite element model of the SOFC stack unit, and perform numerical simulation by applying a cyclic thermal temperature field based on the residual stress distribution field of the electrode plate obtained in step S2 to obtain the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate in the SOFC stack unit under start-stop cycle conditions;

[0009] S4. Analyze the failure mechanism of the materials composing the SOFC electrode plate, construct a prediction model for the thermal fatigue damage of the electrode plate, and use the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate obtained in step S3 to calculate the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles and predict the thermal fatigue life of the electrode plate.

[0010] Further, step S1 specifically includes:

[0011] Determine the material compositions of the various structures of the SOFC stack unit, including: the materials of the anode layer, electrolyte layer, and cathode layer of the electrode plate, the bipolar plate material, and the sealing layer material;

[0012] Through small punch test experiments, obtain the elastic modulus and Poisson's ratio of the materials of the anode layer, electrolyte layer, cathode layer of the electrode plate, and the sealing layer material;

[0013] Through a thermomechanical analyzer or a differential thermal dilatometer, obtain the linear thermal expansion coefficients of the materials of the anode layer, electrolyte layer, cathode layer of the electrode plate, and the sealing layer material;

[0014] Through fatigue crack growth rate experiments, obtain the fatigue parameters of the materials of the anode layer, electrolyte layer, cathode layer of the electrode plate, and the sealing layer material;

[0015] Through mechanical property test experiments of metal materials, obtain the mechanical property parameters related to temperature of the bipolar plate material, including tensile strength, yield strength, elongation, yield point, elastic limit, elastic modulus, and Poisson's ratio.

[0016] Further, step S1 also includes:

[0017] Prepare test specimens of the electrode plate, observe the microstructures at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer of the electrode plate through an electron microscope, and respectively obtain the average pore diameter and average pore spacing at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer of the electrode plate.

[0018] Further, step S2 is specifically:

[0019] Establish a full-scale finite element model of the sintering process of the SOFC electrode plate, apply a sintering temperature field to simulate its sintering process, and obtain the residual stress distribution field of the sintered electrode plate; then establish a finite element model of the electrode plate leveling operation, apply a leveling operation to the sintered electrode plate, and obtain the residual stress distribution field of the electrode plate after the leveling operation.

[0020] Further, when simulating the sintering process of the electrode plate in step S2, the applied sintering temperature field is obtained by measuring the temperature-time change curve of the electrode plate during the actual sintering process.

[0021] Further, the finite element model for the leveling operation of the electrode plate established in step S2 includes the electrode plate, a leveling plate disposed below the electrode plate, and a roller disposed above the electrode plate. A pressure is applied to the roller to make it roll uniformly over the electrode plate to simulate the leveling process.

[0022] Further, during the simulation in step S3, the applied cyclic thermal temperature field is obtained by measuring the temperature-time change curve of the actual stack during the start-stop process.

[0023] Further, the electrode plate thermal fatigue damage prediction model constructed in step S4 is as follows:

[0024] ;

[0025] Where:

[0026] ;

[0027] ;

[0028] ;

[0029] In the formula, is the damage coefficient, and , when , it indicates that the electrode plate has not suffered damage. When , it indicates that the electrode plate has failed; is the microcrack size; is the pore spacing; is the number of cycles of the cyclic load; and are material constants; is the ratio of the maximum principal stress to the minimum principal stress; is the total stress intensity factor, is the stress intensity factor of the type-I crack, is the stress intensity factor of the type-II crack; is the magnitude of the principal stress amplitude for each cycle; is the magnitude of the shear stress amplitude for each cycle.

[0030] The present invention has the following beneficial effects:

[0031] The present invention provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, establishes a prediction model for the thermal fatigue damage of the electrode plate, and also considers the influence of the residual stress during the preparation process of the electrode plate on its fatigue life, which can accurately evaluate the thermal fatigue life of the electrode plate under start-stop cycle conditions, provide theoretical guidance for the stack design, and improve the reliability of the stack design; moreover, the prediction method of the present invention can also predict the degree of thermal fatigue damage of the electrode plate during the operation of the fuel cell and predict its remaining fatigue life, so as to be able to take measures for maintenance and repair in a timely manner, improve the reliability of the fuel cell operation, extend its service life, and ensure the long-term stable operation of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flowchart of the present invention;

[0033] Figure 2 is a mesh diagram of the finite element model of the electrode plate sintering and leveling operation established by the present invention;

[0034] Figure 3 is a mesh diagram of the finite element model of the SOFC stack unit established by the present invention;

[0035] Figure 4 is a thermal cycle curve of the positive thermal stress of the electrode plate under start-stop cycle conditions obtained by the present invention;

[0036] Figure 5 is a schematic diagram of the defect at the electrode plate boundary interface;

[0037] Figure 6 is a curve showing the evolution law of the damage coefficient of the electrode plate obtained by the present invention considering the residual stress with the number of thermal cycles. Among them, (a) and (b) are respectively the trend diagrams of the damage coefficient at the cathode layer - electrolyte layer boundary interface and the anode layer - electrolyte layer boundary interface of the electrode plate with the number of cycles;

[0038] Figure 7 is a curve showing the evolution law of the damage coefficient of the electrode plate obtained by the present invention without considering the residual stress with the number of thermal cycles. Among them, (a) and (b) are respectively the trend diagrams of the damage coefficient at the cathode layer - electrolyte layer boundary interface and the anode layer - electrolyte layer boundary interface of the electrode plate with the number of cycles.

[0039] In the figure, the notations are: 1. Electrode plate; 2. Roller; 3. Flattening plate; 4. Bipolar plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following further describes the specific embodiments of the present invention in conjunction with the drawings and specific embodiments.

[0041] Refer to Figure 1, this embodiment provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, including the following steps S1 - S5.

[0042] S1. According to the material compositions of the structures of each unit of the SOFC stack, prepare test specimens of each material and obtain the relevant parameters of each material.

[0043] Specifically, in this embodiment, the SOFC stack unit mainly includes an electrode plate, a bipolar plate, and a sealing layer. The electrode plate and the sealing layer are both made of ceramic materials, and the bipolar plate is made of a metal material. Among them, the electrode plate is composed of three electrode structures: an anode layer, an electrolyte layer, and a cathode layer, and the electrolyte layer is located between the anode layer and the cathode layer. The anode layer of the electrode plate is made of NiO - YSZ material, the electrolyte layer is made of YSZ material, and the cathode layer is made of LSM material; the sealing layer is a glass - ceramic material; the bipolar plate is Crofer22 APU.

[0044] For the above - mentioned anode layer, electrolyte layer, cathode layer materials of the electrode plate and the above - mentioned sealing layer material, conduct small punch test experiments at different temperatures, and through relevant theoretical calculations, obtain the elastic modulus and Poisson's ratio of each layer of ceramic material of the above - mentioned electrode plate and the ceramic material of the sealing layer at different temperatures.

[0045] For the above - mentioned anode layer, electrolyte layer, cathode layer materials of the electrode plate and the above - mentioned sealing layer material, through the fatigue crack growth rate test, obtain the curve, logarithmize the data points of the material crack growth rate and the stress range, transform them into a linear equation, and use the method of linear regression to fit and obtain the fatigue parameters required for fatigue life prediction , , , which are constants related to the material.

[0046] For the above - mentioned bipolar plate material, conduct mechanical property test experiments of metal materials at different temperatures, such as uniaxial tensile tests, and obtain the mechanical property parameters related to temperature of the bipolar plate material, including tensile strength, yield strength, elongation, yield point, elastic limit, elastic modulus, and Poisson's ratio.

[0047] In addition, this embodiment also prepares test specimens of the electrode plate, and observes the microstructures at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer of the electrode plate through an electron microscope, and respectively obtains the average pore diameter and the average pore spacing at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer of the electrode plate.

[0048] The preparation process of the above - mentioned electrode plate test specimens is as follows:

[0049] (1)The anode layer, electrolyte layer, and cathode layer materials were separately prepared and placed in a ball milling tank. Using absolute ethanol as a solvent, ball milling was carried out on a ball mill to obtain the anode layer, electrolyte layer, and cathode layer slurries;

[0050] (2)First, the anode layer slurry was prepared into an anode layer by the doctor blade method. Then, the electrolyte layer slurry was coated on the anode layer, and co-sintering was carried out at a high temperature. The sintering temperature was 1400 °C, and the sintering time was 2 hours;

[0051] (3)After cooling, the cathode layer slurry was coated on the electrolyte layer, and sintering was carried out again. The sintering temperature was 1375 °C, and the sintering time was 2 hours to prepare the electrode plate.

[0052] The size of the electrode plate prepared above was 60 mm × 60 mm, and the thicknesses of the anode layer, electrolyte layer, and cathode layer were 600 μm, 10 μm, and 40 μm, respectively.

[0053] In addition, during the above preparation process, the sintering temperature-time curve was obtained through a thermocouple.

[0054] S2. A full-scale SOFC electrode plate finite element model was established to simulate the electrode plate preparation process and obtain the residual stress distribution field of the electrode plate.

[0055] Specifically, referring to Figure 2 , in this embodiment, the electrode plate preparation process included two operations: electrode plate sintering and electrode plate leveling. These two operation processes needed to be simulated in this embodiment. During the simulation process of this embodiment, a finite element model of the electrode plate sintering process and a finite element model of the electrode plate leveling operation needed to be established. Among them, the established finite element model of the electrode plate sintering consisted of a rigid sintering flat plate, an anode layer, an electrolyte layer, and a cathode layer. Among them, the anode layer material was NiO-YSZ, the electrolyte layer material was YSZ, and the cathode layer material was LSM; the sizes of the anode layer, electrolyte layer, and cathode layer were 60 × 60 mm, and the thicknesses of the anode layer, electrolyte layer, and cathode layer were 600 μm, 10 μm, and 40 μm, respectively; the finite element model of the electrode plate leveling operation established in this embodiment included an electrode plate, a leveling plate arranged below the electrode plate, and a roller press wheel arranged above the electrode plate. The leveling process was simulated by applying pressure to the roller press wheel to make it roll uniformly over the electrode plate.

[0056] During the simulation process, in this embodiment, first, a finite element model of the electrode plate sintering is established according to the SOFC electrode plate structure and dimensions. The material properties of the electrode plate material are set according to the relevant parameters obtained in step S1, and the classical thermoelastic constitutive model is introduced. The sintering temperature field is applied to simulate the sintering process, and the applied sintering temperature field is obtained by measuring the temperature-time change curve of the electrode plate during the actual sintering process, and the residual stress distribution field of the electrode plate after sintering is obtained. Then, a finite element model of the electrode plate leveling operation is established, and the leveling operation is applied to the sintered electrode plate to obtain the residual stress distribution field of the electrode plate after the leveling operation.

[0057] In addition, to more accurately simulate the above sintering process and obtain the accurate residual stress distribution law. In this embodiment, during the above simulation process, first, the anode layer and the electrolyte layer are sequentially arranged above the rigid sintering flat plate, and then the co-sintering process of the anode layer and the electrolyte layer is numerically simulated to obtain the residual stress distribution field of the electrode plate during the co-sintering process of the anode layer and the electrolyte layer. Then, on this basis, the cathode layer is set, and the sintering process of the entire electrode plate is numerically simulated to obtain the residual stress distribution field of the electrode plate after sintering is completed.

[0058] In addition, in this embodiment, the electrode plate is made of ceramic material, and its plastic deformation ability is poorer than that of conventional metal materials. The classical thermoelastic constitutive model is also introduced during the finite element simulation process, that is:

[0059] ;

[0060] ;

[0061] ;

[0062] ;

[0063] where, is the total strain, is the elastic strain, is the thermal strain, is the initial strain, is the linear thermal expansion coefficient, is the difference between the current temperature and the zero-stress reference temperature, is the stress vector, is the elastic matrix, is the initial stress, is the elastic modulus, is the Poisson's ratio.

[0064] S3. Establish a full-size SOFC stack unit finite element model, and perform numerical simulation by applying a cyclic thermal temperature field based on the residual stress distribution field of the electrode plate obtained in step S2 to obtain the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate in the SOFC stack unit under start-stop cycle conditions.

[0065] Specifically, referring to Figure 3 , the full-size SOFC stack unit finite element model established in this embodiment is established according to the actual stack unit structure. The full-size SOFC stack unit finite element model established in this embodiment specifically includes an electrode plate, a sealing layer, and a bipolar plate. To simplify the calculation process, in this embodiment, the sealing layer and the bipolar plate are only arranged on one side of the anode layer, and the sealing layer is located between the anode layer and the bipolar plate.

[0066] In addition, during the simulation process in this embodiment, the applied cyclic thermal temperature field is obtained by measuring the temperature-time change curve of the actual stack during start-stop. In this embodiment, the temperature during the start-stop process changes within the range of normal temperature to 800 °C.

[0067] In this embodiment, the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate in the SOFC stack unit under start-stop cycle conditions are obtained through simulation, and the data is plotted into a thermal cycle curve. As Figure 4 shown is the thermal cycle curve of the positive thermal stress of the electrode plate under start-stop cycle conditions, and it is compared with the thermal cycle curve of the positive thermal stress without considering the residual stress during the preparation process of the electrode plate. It can be found that the thermal stress considering the residual stress is significantly higher than that without considering the residual stress.

[0068] S4. Analyze the failure mechanism of the SOFC electrode plate composition material, construct a thermal fatigue damage prediction model for the electrode plate, and use the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate obtained in step S3 to calculate the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles and predict the thermal fatigue life of the electrode plate.

[0069] Referring to Figure 5 , in this embodiment, the electrode plate is a ceramic brittle material. Due to the needs of chemical reactions and gas diffusion in its anode layer and cathode layer, there are unevenly sized micropores distributed at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer, which can be regarded as the initial defects existing in the electrode plate material. Therefore, the fracture mechanics method is used for analysis. When an external force acts, an elastic stress field will be formed near the initial defect, and the defect will expand on this stress field until it develops into a macroscopic crack.

[0070] Considering that the position of fatigue failure of the electrode plate usually occurs at the boundaries of each layer, in this embodiment, the Paris formula is modified, and the modified formula is used to describe the fatigue crack propagation process of the electrode plate. The modified Paris formula is:

[0071] ;

[0072] In the formula, is the microcrack size, is the number of cycles of the cyclic load, and are material-related constants, is the ratio of the maximum normal stress to the minimum normal stress, , is the total stress intensity factor.

[0073] Based on the above formula, the damage coefficient is introduced, and , is the microcrack size, represents the pore spacing; when , it indicates that the electrode plate has not suffered damage. When , the electrode plate is considered to have failed.

[0074] Combining the damage coefficient with the modified Paris formula, the thermal fatigue damage prediction model of the electrode plate is obtained as:

[0075] ;

[0076] Where:

[0077] ;

[0078] ;

[0079] ;

[0080] In the formula, is the stress intensity factor of the type-I crack, is the stress intensity factor of the type-II crack; is the magnitude of the normal stress amplitude per cycle, ; is the magnitude of the shear stress amplitude per cycle, .

[0081] The above and can be obtained according to the evolution laws of the positive thermal stress and shear thermal stress of the electrode plate in the start-stop cycle condition of the SOFC stack unit obtained in the above step S3. Specifically, a program can be written in matlab to extract the maximum and minimum values of the positive thermal stress and shear thermal stress data obtained in each cycle, so as to obtain the normal stress amplitude and shear stress amplitude of each cycle.

[0082] In this embodiment, during the calculation process, based on the initial defects existing in the electrode plate material, the average pore diameters at the boundaries between the anode layer and the electrolyte layer and between the cathode layer and the electrolyte layer are respectively regarded as the initial crack lengths on the anode layer side and the cathode layer side; when the micro-crack size extends from the average pore diameter to the average pore spacing, it is regarded that the micropores have developed into macroscopic cracks. When it develops into macroscopic cracks, it indicates that the electrode plate has failed.

[0083] This embodiment uses the established prediction model for the thermal fatigue damage of the electrode plate, and combines the normal stress amplitude and shear stress amplitude of each cycle considering the residual stress obtained in step S3. According to the above crack propagation law, the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles is calculated to predict the thermal fatigue life of the electrode plate. As Figure 6 shown, the trend graphs of the damage coefficients at the interfaces between the cathode layer and the electrolyte layer and between the anode layer and the electrolyte layer of the electrode plate with the number of cycles are respectively obtained. When it is regarded that the electrode plate has failed. At this time, the number of cycles at the interface between the cathode layer and the electrolyte layer is 9 times, and the number of cycles at the interface between the anode layer and the electrolyte layer is 6 times. The smaller value is taken as the thermal fatigue life of the electrode plate, that is, the thermal fatigue life of the electrode plate is 6 cycles.

[0084] In addition, this embodiment also uses the normal stress amplitude and shear stress amplitude of each cycle without considering the residual stress to calculate the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles and predict the thermal fatigue life of the electrode plate. As Figure 7 shown, the trend graphs of the damage coefficients at the interfaces between the cathode layer and the electrolyte layer and between the anode layer and the electrolyte layer of the electrode plate with the number of cycles are respectively obtained. When it is regarded that the electrode plate has failed. At this time, the number of cycles at the interface between the cathode layer and the electrolyte layer is 11 times, and the number of cycles at the interface between the anode layer and the electrolyte layer is 8 times. The smaller value is taken as the thermal fatigue life of the electrode plate, that is, the thermal fatigue life of the electrode plate is 8 cycles.

[0085] Comparing the thermal fatigue lives predicted with and without considering the residual stress, the thermal fatigue life predicted considering the residual stress is significantly lower than that predicted without considering the residual stress. The residual stress in the electrode plate sintering process has a great impact on its thermal fatigue life and cannot be ignored.

[0086] This embodiment predicts the thermal fatigue life of the SOFC electrode plate through the above method, which can provide a theoretical reference for the design of the SOFC stack and preventive maintenance during operation to ensure its long-term stable operation.

[0087] It should be noted that the parts not described in this embodiment are obtained by using the existing technology.

[0088] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, characterized in that: Includes steps: S1. According to the material composition of each structure of the SOFC stack unit, prepare test samples of each material and obtain relevant parameters of each material; S2. Establish a full-size SOFC electrode plate finite element model, simulate the electrode plate preparation process, and obtain the residual stress distribution field of the electrode plate; S3, establishing a full-size SOFC stack unit finite element model, and applying a cyclic thermal temperature field to perform numerical simulation based on the electrode plate residual stress distribution field obtained in step S2, to obtain the evolution law of the positive thermal stress and shear thermal stress of the electrode plate in the SOFC stack unit under the start-stop cycle condition; S4, analyzing the failure mechanism of the constituent materials of the SOFC electrode plate, constructing a thermal fatigue damage prediction model for the electrode plate, and using the evolution law of the positive thermal stress and shear thermal stress of the electrode plate obtained in step S3, calculating the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles, and predicting the thermal fatigue life of the electrode plate; The electrode plate thermal fatigue damage prediction model constructed in step S4 is: ； in: ； ； ； In the formula, is the damage coefficient, and ,when When When , it indicates that the electrode plate fails; is the microcrack size; is the pore spacing; is the number of cyclic loading cycles; and is the material constant; is the ratio of the maximum normal stress to the minimum normal stress; is the total stress intensity factor, is the stress intensity factor of type I crack, is the stress intensity factor of mode II crack; is the normal stress amplitude of each cycle; is the shear stress amplitude of each cycle.

2. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 1, characterized in that: The step S1 specifically includes: Determine the material composition of each structure of the SOFC stack unit, including: electrode plate anode layer, electrolyte layer, cathode layer material, bipolar plate material, and sealing layer material; Through the small punch test, the elastic modulus and Poisson's ratio of the electrode plate anode layer, electrolyte layer, cathode layer material and sealing layer material are obtained; Obtain the linear thermal expansion coefficients of the electrode plate anode layer, electrolyte layer, cathode layer material and sealing layer material by using a thermomechanical analyzer or a differential thermal expansion instrument; Through fatigue crack growth rate test, the fatigue parameters of the electrode plate anode layer, electrolyte layer, cathode layer material and sealing layer material are obtained; Through the mechanical properties test of metal materials, the temperature-related mechanical properties parameters of bipolar plate materials are obtained, including tensile strength, yield strength, elongation, yield point, elastic limit, elastic modulus, and Poisson's ratio.

3. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 2, characterized in that: The step S1 further comprises: Electrode plate test samples were prepared, and the microstructures of the boundaries between the anode layer and the electrolyte layer, and between the cathode layer and the electrolyte layer of the electrode plate were observed by electron microscope to obtain the average pore diameter and average pore spacing of the electrode plate at the boundaries between the anode layer and the electrolyte layer, and between the cathode layer and the electrolyte layer, respectively.

4. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 1, characterized in that: The step S2 is specifically as follows: A finite element model of the sintering process of a full-size SOFC electrode plate is established, and a sintering temperature field is applied to simulate the sintering process, and the residual stress distribution field of the electrode plate after sintering is obtained. Then, a finite element model of the electrode plate leveling operation is established, and a leveling operation is applied to the sintered electrode plate to obtain the residual stress distribution field of the electrode plate after the leveling operation.

5. A method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 4, characterized in that: When simulating the sintering process of the electrode plate in step S2, the applied sintering temperature field is obtained by measuring the temperature-time variation curve of the electrode plate during the actual sintering process.

6. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 4, characterized in that: The electrode plate leveling operation finite element model established in step S2 includes an electrode plate, a leveling plate disposed below the electrode plate, and a roller wheel disposed above the electrode plate. Pressure is applied to the roller wheel to make it roll over the electrode plate at a uniform speed to simulate the leveling process.

7. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 1, characterized in that: In the simulation process in step S3, the applied cyclic thermal temperature field is obtained by measuring the temperature-time variation curve of the actual fuel cell stack during the start-stop process.

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