Thermal fatigue life prediction method for electrode plate of solid oxide fuel cell

Abstract

The invention discloses a thermal fatigue life prediction method of a solid oxide fuel cell electrode plate, and belongs to the technical field of fuel cells. According to the method, a full-size SOFC electrode plate finite element model is established, an electrode plate preparation process is simulated, and an electrode plate residual stress distribution field is obtained; a finite element model of the full-size SOFC electric pile unit is also established, a circulating heat temperature field is applied based on the obtained residual stress distribution field of the electrode plate for numerical simulation, and the evolution rule of the thermal stress of the electrode plate in the electric pile unit under the start-stop circulating working condition is obtained; meanwhile, an electrode plate thermal fatigue damage prediction model is constructed, the evolution rule of the damage coefficient of the electrode plate along with the number of thermal cycles is calculated according to the obtained evolution rule of the thermal stress of the electrode plate, and the thermal fatigue life of the electrode plate is predicted. According to the method, the thermal fatigue life of the electrode plate is predicted, and a theoretical reference can be provided for the design of a galvanic pile and preventive maintenance in an operation process, so that long-term stable operation of the galvanic pile is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of solid oxide fuel cells, and in particular 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) belongs to the third generation of fuel cells. This all-solid-state chemical power generation equipment can directly convert the chemical energy in fuel and oxidant into electrical energy under medium and high temperature (600-1000℃) conditions. It has the advantages of high energy conversion efficiency, low cost, high specific power, wide fuel source, and environmental friendliness. It is widely used in mobile power, combined heat and power, distributed power, transportation and military fields. However, SOFC has not yet been fully commercialized. One of the main reasons is that it is limited by the high temperature strength of SOFC, especially its electrode plate structure. SOFC electrode plates, also known as PEN plates (Positive-Electrolyte-Negative), are composed of a variety of ceramic materials with significant differences in thermal properties. Thermal stress is inevitable during preparation and service, especially when the SOFC stack needs to be frequently started and stopped due to maintenance or work requirements, and thermal fatigue failure is very likely to occur. Fatigue cracking of the PEN plate will not only seriously affect the operating performance of the entire stack, but also once it cracks, it will cause the fuel gas in the battery to leak, which will cause greater safety accidents. Therefore, how to predict the thermal fatigue life of SOFC is a key issue to ensure the long-term stable operation of the SOFC stack. Summary of the invention

[0003] In order 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: The present invention provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, comprising the steps of: 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. Analyze the failure mechanism of the constituent materials of the SOFC electrode plate, construct a thermal fatigue damage prediction model for the electrode plate, and use the evolution law 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.

[0005] Furthermore, 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.

[0006] Furthermore, the step S1 further includes: 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.

[0007] Furthermore, 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.

[0008] Furthermore, when simulating the sintering process of the electrode plate in step S2, the sintering temperature field applied is obtained by measuring the temperature-time variation curve of the electrode plate during the actual sintering process.

[0009] Furthermore, the electrode plate leveling operation finite element model established in step S2 includes an electrode plate, a leveling plate arranged below the electrode plate, and a roller wheel arranged 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.

[0010] Furthermore, in the simulation process in step S3, the cyclic thermal temperature field applied is obtained by measuring the temperature-time variation curve of the actual fuel cell stack during the start-stop process.

[0011] Furthermore, the electrode plate thermal fatigue damage prediction model constructed in step S4 is: ; in: ; ; ; In the formula, is the damage factor, 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.

[0012] The present invention has the following beneficial effects: The present invention provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, establishes a thermal fatigue damage prediction model for the electrode plate, and also takes into account the influence of residual stress in the preparation process of the electrode plate on its fatigue life. The thermal fatigue life of the electrode plate under start-stop cycle conditions can be accurately evaluated, providing theoretical guidance for the design of the fuel cell stack and improving the reliability of the fuel cell stack design. 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 that timely measures can be taken for maintenance and repair, thereby improving the reliability of the fuel cell operation, extending its service life, and ensuring that the fuel cell can operate stably for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flow chart of the present invention; Figure 2 A mesh diagram of the finite element model of the electrode plate sintering and leveling operation established in the present invention; Figure 3 A mesh diagram of the finite element model of the SOFC stack unit established in the present invention; Figure 4 The thermal cycle curve of the positive thermal stress of the electrode plate obtained by the present invention under the start-stop cycle condition; Figure 5 Schematic diagram of the interface defect of the electrode plate boundary; Figure 6 The curve of the evolution of the damage coefficient of the electrode plate with the number of thermal cycles obtained when the residual stress is considered in the present invention, wherein (a) and (b) are respectively the trend diagrams of the damage coefficient at the boundary interface between the cathode layer and the electrolyte layer of the electrode plate and the boundary interface between the anode layer and the electrolyte layer with the number of cycles; Figure 7 The curve of the evolution of the damage coefficient of the electrode plate with the number of thermal cycles obtained when the residual stress is not considered in the present invention, wherein (a) and (b) are 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, respectively.

[0014] Labels in the figure: 1. electrode plate; 2. roller wheel; 3. leveling plate; 4. bipolar plate. DETAILED DESCRIPTION

[0015] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and specific examples.

[0016] Reference Figure 1 This embodiment provides a method for predicting the thermal fatigue life of a solid oxide fuel cell electrode plate, comprising the following steps S1-S5.

[0017] 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.

[0018] 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 made of ceramic materials, and the bipolar plate is made of metal materials. Among them, the electrode plate is composed of a three-layer electrode structure of 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 NiO-YSZ material, the electrolyte layer is YSZ material, and the cathode layer is LSM material; the sealing layer is glass ceramic material; and the bipolar plate is Crofer22 APU.

[0019] For the above-mentioned electrode plate anode layer, electrolyte layer, cathode layer materials and the above-mentioned sealing layer materials, small punch test experiments are carried out at different temperatures, and through relevant theoretical calculations, the elastic modulus and Poisson's ratio of the ceramic materials of each layer of the above-mentioned electrode plate and the sealing layer ceramic materials at different temperatures are obtained.

[0020] For the above-mentioned electrode plate anode layer, electrolyte layer, cathode layer materials and the above-mentioned sealing layer materials, fatigue crack growth rate test is performed to obtain The data points of the crack growth rate and stress range of the material are logarithmized and converted into linear equations. The fatigue parameters required for fatigue life prediction are obtained by linear regression. , , , is a constant related to the material.

[0021] For the above-mentioned bipolar plate materials, mechanical properties test experiments of metal materials are carried out at different temperatures, such as uniaxial tensile test, to obtain temperature-related mechanical performance parameters of the bipolar plate materials, including tensile strength, yield strength, elongation, yield point, elastic limit, elastic modulus, and Poisson's ratio.

[0022] In addition, this embodiment also prepares electrode plate test samples, and observes the microstructure of the boundary between the anode layer and the electrolyte layer, and the boundary between the cathode layer and the electrolyte layer of the electrode plate through an electron microscope, and obtains the average pore diameter and the average pore spacing of the electrode plate at the boundary between the anode layer and the electrolyte layer, and the boundary between the cathode layer and the electrolyte layer, respectively.

[0023] The preparation process of the above electrode plate test sample is as follows: (1) preparing the materials of the anode layer, electrolyte layer, and cathode layer respectively, placing them in a ball milling jar respectively, and using anhydrous ethanol as a solvent, ball milling them on a ball mill to obtain slurries of the anode layer, electrolyte layer, and cathode layer; (2) firstly preparing the anode layer slurry by rolling process to form the anode layer, then coating the electrolyte layer slurry on the anode layer, and co-sintering at high temperature, the sintering temperature is 1400°C, and the sintering time is 2 hours; (3) After cooling, the cathode layer slurry is coated on the electrolyte layer and sintered again at a sintering temperature of 1375° C. for 2 hours to prepare an electrode plate.

[0024] The size of the electrode plate prepared above is 60 mm×60 mm, and the thicknesses of the anode layer, electrolyte layer, and cathode layer are 600 μm, 10 μm, and 40 μm, respectively.

[0025] In addition, during the above preparation process, a sintering temperature-time curve is also obtained through a thermocouple.

[0026] 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.

[0027] Specifically, refer to Figure 2In this embodiment, the electrode plate preparation process includes two operations: electrode plate sintering and electrode plate leveling. This embodiment needs to simulate these two operation processes. In the simulation process, this embodiment needs to establish a finite element model of the electrode plate sintering process and a finite element model of the electrode plate leveling operation. Among them, the established electrode plate sintering finite element model consists of a rigid sintered flat plate and an anode layer, an electrolyte layer, and a cathode layer, wherein the anode layer material is NiO-YSZ, the electrolyte layer material is YSZ, and the cathode layer material is LSM; the size of the anode layer, the electrolyte layer, and the cathode layer is 60×60mm, and the thickness of the anode layer, the electrolyte layer, and the cathode layer is 600μm, 10μm, and 40μm, respectively; the electrode plate leveling operation finite element model established in this embodiment includes an electrode plate, a leveling plate arranged under the electrode plate, and a roller arranged above the electrode plate. The roller applies pressure to the roller to make it roll over the electrode plate at a uniform speed to simulate the leveling process.

[0028] During the simulation process, in this embodiment, a finite element model of electrode plate sintering is first established according to the structure and size of the SOFC electrode plate, 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. A sintering temperature field is applied to simulate the sintering process, and the applied sintering temperature field is obtained by measuring the temperature-time variation curve of the electrode plate during the actual sintering process to obtain the residual stress distribution field of the electrode plate after sintering; then a finite element model of the electrode plate leveling operation is established, and a leveling operation is applied to the electrode plate after sintering to obtain the residual stress distribution field of the electrode plate after the leveling operation.

[0029] In addition, in order to more accurately simulate the above sintering process and obtain accurate residual stress distribution law, in the above simulation process, the present embodiment first arranges the anode layer and the electrolyte layer in sequence above the rigid sintering plate, and then numerically simulates the co-sintering process of the anode layer and the electrolyte layer 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 arranged, 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.

[0030] In addition, in this embodiment, the electrode plate is made of ceramic material, which has poorer plastic deformation ability than conventional metal materials. A classical thermoelastic constitutive model is also introduced in the finite element simulation process, namely: ; ; ; ; In the formula, 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 elasticity matrix, is the initial stress, is the elastic modulus, is Poisson's ratio.

[0031] S3. Establish a finite element model of a full-size SOFC stack unit, and apply a cyclic thermal temperature field to perform numerical simulation based on the residual stress distribution field of the electrode plate 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.

[0032] Specifically, refer 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, this embodiment only sets a sealing layer and a bipolar plate on one side of the anode layer, and the sealing layer is located between the anode layer and the bipolar plate.

[0033] In addition, in the simulation process of this embodiment, 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. In this embodiment, the start-stop process temperature varies in the range of room temperature to 800°C.

[0034] This embodiment simulates 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, and plots the data into a thermal cycle curve, such as Figure 4 The figure shows the thermal cycle curve of the positive thermal stress of the electrode plate under the start-stop cycle condition, and compares it with the thermal cycle curve of the positive thermal stress without considering the residual stress in the preparation process of the electrode plate. It can be found that the thermal stress after considering the residual stress is significantly higher than the thermal stress without considering the residual stress.

[0035] S4. Analyze the failure mechanism of the constituent materials of the SOFC electrode plate, construct a thermal fatigue damage prediction model for the electrode plate, and use the evolution law 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.

[0036] Reference Figure 5In this embodiment, the electrode plate is a ceramic brittle material. Due to the needs of chemical reaction and gas diffusion, the anode layer and the cathode layer have unevenly distributed micropores at the boundary between the anode layer and the electrolyte layer, and at the boundary between the cathode layer and the electrolyte layer. These can be regarded as initial defects in the electrode plate material. Therefore, the fracture mechanics method is used for analysis. When there is an external force, 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 macro crack.

[0037] Considering that the fatigue failure position of the electrode plate is usually at the boundary of each layer, the present embodiment modifies the Paris formula, and uses the modified formula to describe the fatigue crack propagation process of the electrode plate. The modified Paris formula is: ; In the formula, is the microcrack size, is the number of cyclic loading cycles, and is a constant related to the material, is the ratio of the maximum normal stress to the minimum normal stress, , is the total stress intensity factor.

[0038] Based on the above formula, the damage coefficient is introduced ,and , is the microcrack size, represents the pore spacing; when When When the electrode plate fails,

[0039] The damage factor Combined with the modified Paris formula, the electrode plate thermal fatigue damage prediction model is obtained as follows: ; in: ; ; ; In the formula, 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, .

[0040] Above and The positive thermal stress and shear thermal stress evolution law of the electrode plate in the SOFC stack unit under the start-stop cycle condition obtained in the above step S3 can be obtained. Specifically, a MATLAB program can be written 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 positive stress amplitude and shear stress amplitude of each cycle.

[0041] In the calculation process of this embodiment, based on the initial defects of the electrode plate material, the average pore diameters at the boundary between the anode layer and the electrolyte layer and the boundary 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 microcrack size When the average pore diameter expands to the average pore spacing, the micropores are considered to have developed into macro cracks. When they develop into macro cracks, it indicates that the electrode plate has failed.

[0042] This embodiment uses the established thermal fatigue damage prediction model for the electrode plate, and combines the normal stress amplitude and shear stress amplitude of each cycle when considering the residual stress obtained in step S3, and calculates the evolution law of the damage coefficient of the electrode plate with the number of thermal cycles according to the above crack growth law, and predicts the thermal fatigue life of the electrode plate. Figure 6 As shown in the figure, the damage coefficients at the interface between the cathode layer and the electrolyte layer and the interface between the anode layer and the electrolyte layer of the electrode plate change with the number of cycles. When , the electrode plate is considered to have failed. At this time, the number of cycles at the cathode layer-electrolyte layer boundary interface is 9 times, and the number of cycles at the anode layer-electrolyte layer boundary interface 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.

[0043] 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. Figure 7 As shown in the figure, the damage coefficients at the interface between the cathode layer and the electrolyte layer and the interface between the anode layer and the electrolyte layer of the electrode plate change with the number of cycles. When , the electrode plate is considered to have failed. At this time, the number of cycles at the cathode layer-electrolyte layer boundary interface is 11 times, and the number of cycles at the anode layer-electrolyte layer boundary interface 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.

[0044] Comparing the thermal fatigue life predicted by considering residual stress with that predicted by not considering residual stress, the thermal fatigue life predicted by considering residual stress is significantly lower than that predicted by not considering residual stress. The residual stress in the sintering process of the electrode plate has a great influence on its thermal fatigue life and cannot be ignored.

[0045] 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 the preventive maintenance during operation to ensure its long-term stable operation.

[0046] It should be noted that the parts not described in this embodiment are obtained by using existing technologies.

[0047] 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 technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for predicting 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. Analyze the failure mechanism of the constituent materials of the SOFC electrode plate, construct a thermal fatigue damage prediction model for the electrode plate, and use the evolution law 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.

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.

8. The method for predicting thermal fatigue life of a solid oxide fuel cell electrode plate according to claim 1, characterized in that: The electrode plate thermal fatigue damage prediction model constructed in step S4 is: ； in: ； ； ； In the formula, is the damage factor, 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.

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