A method and device for modeling multi-physical fields of a membrane electrode electrolyzer

Abstract

The application discloses a kind of membrane electrode electrolytic cell multi-physical field modeling method and device, comprising the following steps: step S1, obtains the structure parameter, physical property parameter and chemical reaction parameter related to device;Step S2, according to the physical property parameter obtained, constructs MEA multi-physical field numerical model;Step S3, the calculation result of numerical model is analyzed, determines the salting-out potential and salting-out current density of CO2 membrane electrode assembly under the operation of working condition;Step S4, adjusts the multiple design parameters of MEA, determines the most suitable design parameter according to the occurrence of salting-out and in combination with the comprehensive performance of device;Step S5, under the corresponding salting-out potential, the occurrence of salting-out is inhibited by regulating relevant input parameters.The MEA multi-physical field model constructed by the application more truly reflects the information of various design parameters MEA under working condition or non-working condition, helps to deepen the understanding of the influencing factor mechanism of substance transfer on MEA electrochemical performance, and provides guidance for the practical application of CO2MEA.

Description

Technical Field

[0001] This invention relates to the field of electrolyzers, and more particularly to a method and apparatus for modeling multiphysics fields in membrane electrode electrolyzers. Background Technology

[0002] In the context of new energy sources, the development of efficient energy conversion technologies has become urgent. Among various energy conversion technologies, electrolysis is one of the most promising approaches. In practice, three types of electrochemical devices are used for electrolysis: H-type electrolyzers, flow-through electrolyzers, and membrane electrode assemblies (MEAs). H-type and flow-through electrolyzers are the two types of electrolyzers most commonly used in laboratories for electrolysis experiments. H-type electrolyzers have a simple structure and are easy to assemble. The cathode and anode chambers are separated by an ion-exchange membrane, allowing for rapid evaluation of catalyst performance. However, due to limitations in solubility and mass transfer processes, the reaction current density in H-type electrolyzers is typically limited to 20 mA cm⁻¹. -2 The current density is far below commercial levels, limiting its practical application. To overcome this limitation, flow-through electrolyzers utilize gas diffusion electrodes, significantly shortening the gas diffusion distance. During the reaction, reactants are directly transported to the back of the cathode via the gas phase and rapidly penetrate the gas diffusion electrode to reach the catalyst surface for reaction, resulting in a significant increase in current density. However, due to the significant ohmic resistance of the electrolyte layer in the flow-through cell, its energy efficiency has remained low. MEAs, with their lower ohmic losses and the absence of electrolyte at the cathode, hold promise for further improving electrolysis performance.

[0003] However, due to the complex structure of MEAs, some problems exist in their application. Taking CO2 MEAs as an example, salting out has always been a problem. Salting out leads to a decrease in the porosity of the catalyst layer and porous electrode, inhibiting mass transfer between CO2 and the reaction sites within the flow channel, reducing the reaction current, and simultaneously intensifying the hydrogen evolution reaction, thus decreasing the Faradaic efficiency of the product. Since the cathode reaction produces OH... - The reaction occurs because, under high current density, the pH value of the cathode catalyst layer will increase, and CO2 and OH react. - The homogeneous reaction intensified, accelerating the CO32--- 2- and HCO3 - On the other hand, cations in the anolyte migrate towards the cathode through the anion exchange membrane under the influence of the electric field. When the limiting concentration is reached, that is, when the product of ion concentrations exceeds the solubility product, salting out will theoretically occur. Considering that cations provide an essential local electric field effect in the CO2 electroreduction process, and that MEAs only have practical application value when operating at high current densities, this inevitably leads to salting out.

[0004] Given the problems that exist in the practical application of MEA, it is necessary to design MEA parameters reasonably to avoid many problems to the greatest extent, and to deal with the problems in MEA operation through certain strategies. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for modeling multiphysics fields in a membrane electrode electrolyzer, in order to solve the problems mentioned in the background art.

[0006] To achieve the above-mentioned objectives, one aspect of the present invention provides a method for modeling multiphysics fields in a membrane electrode electrolyzer, comprising the following steps:

[0007] Step S1: Obtain the device-related structural parameters, physical property parameters, and chemical reaction parameters;

[0008] Step S2: Based on the obtained physical property parameters, construct a MEA multiphysics numerical model. The multiphysics field includes gas phase concentration field, liquid phase concentration field, gas phase pressure field, liquid phase pressure field, ionomer water mass transfer, solid phase potential field, liquid phase potential field, and salting-out field.

[0009] Step S3: Analyze the calculation results of the numerical model to determine the salting-out potential and salting-out current density of the CO2 membrane electrode assembly under operating conditions.

[0010] Step S4: Adjust various design parameters of MEA, and determine the most suitable design parameters based on the salting-out situation and the overall performance of the device.

[0011] Step S5: At the corresponding salting-out potential, the occurrence of salting-out is suppressed by adjusting the relevant input parameters.

[0012] Furthermore, the gas phase concentration field is a mixture-averaged model used to describe the mass transfer process of gaseous substances within the anode and cathode, and its expression is:

[0013]

[0014] Where n j It is the flux of gaseous substance j, ρ g It is the density of the gas phase. ω is the effective diffusion coefficient of gaseous substance j. j It is the mass fraction of gaseous substance j, M n ρ is the average molar mass of the gas mixture. i It is the partial density of gaseous substances, u g It is the convection velocity of the gas phase.

[0015] Furthermore, the liquid phase concentration field is described by the Nernst–Planck equation, which describes the mass transfer process of the liquid phase material within the anode and cathode. Its expression is as follows:

[0016]

[0017] Where n i It is the flux of liquid phase substance i. c is the effective diffusion coefficient of liquid phase substance i. i It is the molar concentration of liquid phase substance i, z i Here, φ is the charge number of liquid substance i, F is the Faraday constant, R is the molar gas constant, T is the temperature, and φ is the charge number of liquid substance i. l It is the liquid phase potential.

[0018] Furthermore, the gas-liquid phase pressure field is described by Darcy's law, and its expression is:

[0019]

[0020] Among them, u m It is the convection velocity of medium m. It is the effective permeability of medium m, μ m It is the dynamic viscosity of the medium, p m It is the pressure of medium m.

[0021] Furthermore, the solid-liquid phase potential satisfies Ohm's law, the expression of which is as follows:

[0022]

[0023] i l =F∑ i z i n i

[0024]

[0025] Among them, i s It is the solid-state current density, i l It is the liquid phase current density. It is the effective specific surface area, i k It is the current density of electrode reaction k.

[0026] Furthermore, the reaction rate of the salted-out substance is expressed as follows:

[0027]

[0028] Where R is the salting-out reaction rate, ε is the salt volume fraction, k is the deposition rate constant, and K sp It is the solubility product of the salt, and s is the stoichiometric coefficient.

[0029] Furthermore, the analysis process in step S3 includes comparing the ion concentration product with the salt solubility product under the steady-state model. If the ion concentration product is greater than the salt solubility product, it is considered that salting out will occur. The potential and current density under this condition are the salting out potential and salting out current density.

[0030] Furthermore, the design parameters regulated in step S4 include the thickness of the catalyst layer, the specific surface area of ​​the catalyst layer, the thickness of the anion exchange membrane, and the ion exchange capacity of the anion exchange membrane.

[0031] Furthermore, the response strategy in step S5 includes adjusting the concentration of the anolyte and the voltage applied to the device. By changing the above input conditions, salting out can be suppressed and the current density of the device can be maintained.

[0032] Another aspect of the present invention provides a modeling device for multiphysics fields in a membrane electrode electrolyzer, comprising a parameter acquisition module, a model building module, a numerical analysis module, a parameter adjustment module, and an application module, wherein:

[0033] The parameter acquisition module is used to acquire device-related structural parameters, physical property parameters, and chemical reaction parameters.

[0034] The model building module is used to construct a MEA multiphysics numerical model based on the acquired physical property parameters. The multiphysics fields include gas phase concentration field, liquid phase concentration field, gas phase pressure field, liquid phase pressure field, ionomer water mass transfer, solid phase potential field, liquid phase potential field, and salting-out field.

[0035] The numerical analysis module is used to analyze the calculation results of the numerical model and determine the salting-out potential and salting-out current density of the CO2 membrane electrode assembly under operating conditions.

[0036] The parameter adjustment module is used to adjust various design parameters of the MEA, and determine the most suitable design parameters based on the salting-out situation and the overall performance of the device.

[0037] The application module is used to suppress salting out by adjusting relevant input parameters at the corresponding salting-out potential.

[0038] Compared with existing technologies, this system and method have the following advantages:

[0039] 1. This invention employs a multiphysics numerical model and, through finite element analysis, provides the performance of MEA devices and their material concentration distribution, pressure distribution, and potential distribution under different design parameters.

[0040] 2. This invention predicts the salting-out potential and salting-out current density of MEA under the given design parameters by comparing the magnitude of the ion concentration product and the solubility product of the salt, and suppresses salting-out and maintains good electrochemical performance through relevant strategies.

[0041] 3. This invention has superior computational efficiency and accurate calculation results, which facilitates the research on designing reasonable MEA structures and is conducive to promoting the commercialization of MEA. Attached Figure Description

[0042] Figure 1 This is a flowchart of a multiphysics modeling method for a membrane electrode electrolyzer.

[0043] Figure 2 This is a schematic diagram of the MEA one-dimensional model under example parameters.

[0044] Figure 3 The image shows the polarization curves of the MEA under example parameters.

[0045] Figure 4 The figure shows the results of maintaining the electrochemical performance of the MEA by changing the concentration of the anolyte under constant voltage to suppress salting out.

[0046] Figure 5 The figure shows the results of maintaining the electrochemical performance of the MEA by varying the applied voltage under constant anolyte concentration to suppress salting out.

[0047] Figure 6 This is a wettability diagram corresponding to the capillary pressure of different materials in this model. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] like Figure 1 The diagram shown is a flowchart of the method of this invention. This embodiment of the invention takes the MEA (Multiphysics Analysis) process of CO2 electrolysis as an example to construct a CO2 MEA multiphysics numerical model. This modeling and analysis method mainly includes the following five steps.

[0050] Step S1: Obtain the device-related structural parameters, physical property parameters, and chemical reaction parameters.

[0051] The structural parameters include the porosity, thickness, and cross-sectional area of ​​the flow channel of the material; the physical property parameters include electrical conductivity, permeability, diffusion coefficient, viscosity, ion exchange capacity of the ion exchange membrane, and membrane density of the ion exchange membrane; and the chemical reaction parameters include the forward and reverse rate constants of the homogeneous reaction, equilibrium coefficient, exchange current density of the BV equation, transfer coefficient, and reference equilibrium potential. Specific parameters are shown in Table 1.

[0052]

[0053]

[0054]

[0055]

[0056] Step S2: Construct the MEA multiphysics numerical model based on the obtained physical property parameters.

[0057] Based on the geometric parameters obtained in step S1, a structure can be constructed as follows: Figure 2 The one-dimensional model shown has a multiphysics setting including governing equations and boundary conditions, as expressed below.

[0058] In the model, the mass conservation equations for each substance are as follows:

[0059]

[0060] Among them, c i / j and n i / j These represent the concentration and flux of the substances, respectively. The subscript i indicates liquid phase substances, j indicates gaseous phase substances, and ε represents the flux. m Represents the phase volume fraction, where the subscript m can represent the gas phase (g), liquid phase (l), ionomer phase (i), and solid phase (s), respectively. R B,i Represents a homogeneous reaction source term, occurring only in the liquid and ionomer phases, R CT,i / j Represents the electrode reaction source term, R PT,i / j This represents the source of the inherited quality.

[0061] In this example, the gaseous substance involved in the model is H2O. (g) CO 2(g) CO (g) H 2(g) O 2(g) and N 2(g) , where N 2(g) The calculations were performed based on the principle of mass conservation. The specific gas distribution is as follows: H₂O is present at the cathode. (g) CO 2(g) CO (g) H 2(g) and N 2(g) CO is present at the anode. 2(g) O 2(g) and N 2(g) The gas-phase mass transfer model uses a mixture-average model, and the describing equations for the fluxes of each gas phase substance are as follows:

[0062]

[0063] Where, ρ g It is the density of the gas phase. ω is the effective diffusion coefficient of gaseous substance j. j It is the mass fraction of gaseous substance j, M n It is the average molar mass of the gas mixture, expressed by the equation M j ρ is the molar mass of substance j. i It is the partial density of the gaseous substance, expressed by the equation ρ. j =ρ g ω j Calculate, u g This refers to the convection velocity in the gas phase. The binary diffusion coefficient D for substances j and k. jk Calculated using the following formula

[0064]

[0065] v p This is the diffusion volume of the substance, which can be found in the parameter table. Effective diffusion coefficient. Using the volume fraction ε of the medium m and tortuosity v m Correction was performed using the Bruggeman relation.

[0066]

[0067] The pressure fields of the gas and liquid phases are controlled by Darcy's law.

[0068]

[0069] Among them, u m Q is the convection velocity of medium m. m It is a quality source item. It is the effective permeability of medium m, μ m It is the dynamic viscosity of the medium, p m It is the pressure of medium m.

[0070] In this example, the liquid phase substance involved in the model is CO. 2(l) , and It exists in ion exchange membranes, ionomers, and liquid water.

[0071] The liquid-phase mass transfer model uses dilute solution theory, and the flux of each liquid phase substance is described by the Nernst–Planck equation.

[0072]

[0073] in, c is the effective diffusion coefficient of liquid phase substance i. i It is the molar concentration of liquid phase substance i, z iφ is the charge number of liquid phase substance i, F is the Faraday constant, 96485 C / mol, and φ is the charge number of liquid phase substance i. l It is the liquid phase potential.

[0074] The water flux in the ionomer consists of two phases: a concentration gradient contributing phase and an electrodialysis contributing phase, as shown in the following expression.

[0075]

[0076] D w ξ is the diffusion coefficient of water, and ξ is the electroosmotic coefficient of water.

[0077] In this example, the following homogeneous reaction exists throughout the entire liquid phase concentration field.

[0078]

[0079] Where, k i and k -i These represent the forward and reverse reaction rates, respectively. The equilibrium constant can be determined based on the entropy change of the reaction (ΔS). i ) and enthalpy change (ΔH) i )Calculated using the van't Hoff equation:

[0080]

[0081] The general expression for the homogeneous reaction source term is as follows:

[0082]

[0083] Among them, s i Let be the stoichiometric coefficient of substance i in the equation.

[0084] In this example, the oxygen evolution reaction (OER) occurs at the anode of the membrane electrode assembly, the hydrogen evolution reaction (HER) occurs at the cathode, and most importantly, the CO2 reduction reaction (also known as the CO evolution reaction, COER) occurs. The reaction current densities of these electrode reactions are given by the BV equation:

[0085]

[0086] Among them, c ref =1[M] is the reference concentration, α is the transfer coefficient, i 0,k Let η be the exchange current density of reaction k. k For the overpotential of reaction k, i 0,k and η k The expression is as follows

[0087]

[0088] Among them, Ak E is the pre-exponential factor of reaction k. a,k φ is the apparent activation energy of reaction k. s For solid-state potential, Let be the reference equilibrium potential for reaction k. Electron transfer in the solid phase (including the catalyst layer and porous diffusion layer) is controlled by the following equation.

[0089]

[0090] Among them, i s It is the solid-state current density, i l It is the liquid phase current density, and its expressions are as follows:

[0091]

[0092] in, It is the effective conductivity.

[0093] The general expression for the electrode reaction source term is as follows:

[0094]

[0095] in, The effective specific surface area is S, where S is the wettability, which can be determined according to... Figure 6 capillary pressure (p) c =p l -p g This is obtained by mapping it to the wetting curve. n k denoted as , where is the number of electrons transferred in reaction k.

[0096] In this example, phase mass transfer includes the mass transfer of CO2 at the anode and the mass transfer of CO2 and H2O at the cathode. The general expression for the phase mass source term is as follows:

[0097]

[0098] Where, k MT,j The mass transfer rate is denoted as .

[0099] For CO2 MEA, there is a special case of salting out. This example considers the salting out of K2CO3.

[0100]

[0101] Corresponding to the source term of matter is

[0102]

[0103] in The volume fraction of K2CO3. Let be the deposition rate constant. It is the solubility product of K2CO3.

[0104] The volume fraction of deposited K2CO3 reduces the porosity of the system.

[0105]

[0106] The volume fraction of each phase is calculated as follows:

[0107]

[0108] ε l =ε m S m

[0109] ε l =ε m (1-S m )

[0110] in f is the intrinsic porosity of the medium. i,m This represents the content of ionomers in the pores.

[0111] Due to the presence of ionomers, there are differences in charge density between different domains, resulting in a discontinuous ion concentration distribution that follows Donnan boundary conditions, i.e.

[0112]

[0113] The boundary condition for the electric potential, K, is obtained from electroneutrality. + The concentration boundary conditions are given by the Donnan potential, as detailed in the table below.

[0114]

[0115]

[0116] Other boundary conditions such as electric potential, concentration, and pressure are shown in the table below.

[0117]

[0118] Where, k MT,i The mass transfer coefficient, which is related to the Sherwood–Reynold–Schmidt number, is expressed as follows:

[0119]

[0120] Among them, L elec ρ is the electrode thickness. l v is the density of the electrolyte. l =q l / A elec Let q be the electrolyte flow rate.l A is the electrolyte flow rate. elec μ is the cross-street area of ​​the flow channel. l This refers to the dynamic viscosity of the electrolyte.

[0121] The simulation platform used in this embodiment is the COMSOL Multiphysics simulation platform, and a suitable mesh is manually constructed: a 0.1 μm mesh is set on all domains, and a 1 nm mesh is set on all boundaries.

[0122] Step S3: Analyze the calculation results of the numerical model to determine the salting-out potential and salting-out current density of the CO2 membrane electrode assembly under operating conditions. The criterion for determining whether salting-out occurs in the membrane electrode assembly under these conditions is the solubility product of the salt (i.e.,...). Is it greater than If the solubility product is greater than This indicates that the membrane electrode assembly has reached the conditions for salt precipitation under this operating condition. The corresponding voltage and current densities can be considered as the salt precipitation potential and salt precipitation current density of the membrane electrode assembly. More accurately, this means that when the solubility product of the salt initially exceeds... Even within a short period, salting out of the membrane electrode assembly may not occur, because the rate of salting out is related to the volume fraction of salt ε in the system, the reaction rate constant k, and the solubility product. The difference is related to the operating conditions, so a slightly higher operating condition than the salting-out potential and current density is required for salting-out to have an observable impact on the membrane electrode assembly. Furthermore, the higher the potential and current density, the greater the impact of salting-out on the membrane electrode assembly, and the greater the deviation between its theoretical and actual performance. The numerical model in step S3 is a steady-state model, meaning it does not consider the impact of salting-out on the device and only predicts the potential at which salting-out occurs and its electrochemical performance. Its polarization curve is shown in... Figure 3 As shown.

[0123] Step S4 involves adjusting various design parameters of the MEA to determine the most suitable parameters. These parameters include catalyst layer thickness, catalyst layer specific surface area, ion exchange capacity of the ion exchange membrane, and ion exchange membrane thickness, and the analytical method of step S3 is repeated. In practice, the specific approach is to modify the parameters to be optimized in the parameter list of step S1. To control variables, only one parameter is increased or decreased at a time, and then the calculation is performed. The discrimination method of step S3 is used to determine the impact of the parameter change on the salting-out potential and salting-out current of the membrane electrode assembly. After several iterations, this step determines the most suitable design parameters for the membrane electrode assembly.

[0124] Step S5 involves solving a transient model of the MEA with optimal design parameters under conditions slightly above the salting-out potential. This simulates the salting-out process of the MEA under operating conditions. Multiple strategies (adjusting relevant input parameters) are employed to suppress salting-out and maintain good electrochemical performance of the device. The numerical model is transient, meaning the applied voltage exceeds the salting-out potential. The impact of salting-out on the device is considered, and strategies such as adjusting input parameters including the anolyte concentration and the applied voltage are used to suppress salting-out and maintain the device's electrochemical performance. Figure 4 The graph shows the results of suppressing salting-out and maintaining the electrochemical performance of the MEA by changing the anolyte concentration under constant voltage. From 0 to 1000 seconds, the anolyte feed concentration was 0.5 M. At this concentration, significant salting-out (dashed line) appeared in the MEA after 800 seconds, and the current density (solid line) also showed a significant decrease. At 1000 seconds, the anolyte concentration switched to 0.2 M, and the volume fraction of salting-out decreased significantly, while the current density continued to decrease for a period before only slightly increasing. At 1500 seconds, the anolyte concentration switched back to 0.5 M, and the volume fraction of salting-out increased again, while the current density also increased significantly before slightly decreasing. Figure 5 The figure shows the results of maintaining the electrochemical performance of the MEA by varying the applied voltage to suppress salting-out under constant anolyte concentration. From 0 to 1000 seconds, the applied voltage at the anode was 3.25V. At this voltage, significant salting-out (dashed line) occurred in the MEA after 800 seconds, and the current density (solid line) also showed a significant decrease. At 1000 seconds, the applied voltage at the anode switched to 3.2V, and the volume fraction of salting-out decreased significantly. The current density decreased momentarily at 1000 seconds and then increased slightly. At 1500 seconds, the applied voltage at the anode switched back to 3.25V, and the volume fraction of salting-out increased again, while the current density increased momentarily at 1500 seconds and then decreased slightly.

[0125] This invention is built on the COMSOL Multiphysics platform. Using the COMSOL Multiphysics model developer, the multiphysics fields of the MEA are set, including the gas-liquid phase concentration field, gas-liquid phase pressure field, and solid-liquid phase potential field. Reasonable initial values ​​and boundary conditions are set, and the built-in mesh generation function of the software is used to generate the mesh. A steady-state study module is added to solve for the concentration field, pressure field, and potential field of the model under different parameters. At this time, the salting-out module is temporarily disabled, and the salting-out potential of the CO2 MEA is determined. Then, a transient study module is added, and the salting-out module is enabled to solve for the impact of salting-out on the MEA at different times, as well as the changes in system performance after applying the strategy.

[0126] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for modeling multiphysics fields in a membrane electrode electrolyzer, characterized in that, Includes the following steps: Step S1: Obtain the device-related structural parameters, physical property parameters, and chemical reaction parameters; Step S2: Based on the obtained physical property parameters, construct a MEA multiphysics numerical model. The multiphysics field includes gas phase concentration field, liquid phase concentration field, gas phase pressure field, liquid phase pressure field, ionomer water mass transfer, solid phase potential field, liquid phase potential field, and salting-out field. Step S3: Analyze the calculation results of the numerical model to determine the salting-out potential and salting-out current density of the CO2 membrane electrode assembly under operating conditions. Step S4: Adjust various design parameters of MEA, and determine the most suitable design parameters based on the salting-out situation and the overall performance of the device. Step S5: At the corresponding salting-out potential, the occurrence of salting-out is suppressed by adjusting the relevant input parameters.

2. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The gas phase concentration field is a mixture average model used to describe the mass transfer process of gaseous substances inside the anode and cathode, and its expression is: Where n j It is the flux of gaseous substance j, ρ g It is the density of the gas phase. ω is the effective diffusion coefficient of gaseous substance j. j It is the mass fraction of gaseous substance j, M n ρ is the average molar mass of the gas mixture. i It is the partial density of gaseous substances, u g It is the convection velocity of the gas phase.

3. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The liquid phase concentration field is described by the Nernst–Planck equation, which describes the mass transfer process of the liquid phase material inside the anode and cathode. Its expression is as follows: Where n i It is the flux of liquid phase substance i. c is the effective diffusion coefficient of liquid phase substance i. i It is the molar concentration of liquid phase substance i, z i Here, φ is the charge number of liquid substance i, F is the Faraday constant, R is the molar gas constant, T is the temperature, and φ is the charge number of liquid substance i. l It is the liquid phase potential.

4. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The gas-liquid phase pressure field is described by Darcy's law, and its expression is: Among them, u m It is the convection velocity of medium m. It is the effective permeability of medium m, μ m It is the dynamic viscosity of the medium, p m It is the pressure of medium m.

5. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The solid-liquid phase potentials satisfy Ohm's law, and its expression is as follows: Among them, i s It is the solid-state current density, i l It is the liquid phase current density. It is the effective specific surface area, i k It is the current density of electrode reaction k.

6. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The reaction rate of the salt-out substance is expressed as follows: Where R is the salting-out reaction rate, ε is the salt volume fraction, k is the deposition rate constant, and K sp It is the solubility product of the salt, and s is the stoichiometric coefficient.

7. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The analysis process in step S3 includes comparing the ion concentration product with the salt solubility product under the steady-state model. If the ion concentration product is greater than the salt solubility product, it is considered that salting out will occur. The potential and current density under this condition are the salting out potential and salting out current density.

8. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The design parameters regulated in step S4 include the thickness of the catalyst layer, the specific surface area of ​​the catalyst layer, the thickness of the anion exchange membrane, and the ion exchange capacity of the anion exchange membrane.

9. The multiphysics modeling method for a membrane electrode electrolyzer according to claim 1, characterized in that, The strategy in step S5 includes adjusting the concentration of the anolyte and the voltage applied to the device. By changing the above input conditions, salt precipitation can be suppressed and the current density of the device can be maintained.

10. A modeling device for multiphysics fields in a membrane electrode electrolyzer, characterized in that, It includes a parameter acquisition module, a model building module, a numerical analysis module, a parameter tuning module, and an application module, among which: The parameter acquisition module is used to acquire device-related structural parameters, physical property parameters, and chemical reaction parameters. The model building module is used to construct a MEA multiphysics numerical model based on the acquired physical property parameters. The multiphysics fields include gas phase concentration field, liquid phase concentration field, gas phase pressure field, liquid phase pressure field, ionomer water mass transfer, solid phase potential field, liquid phase potential field, and salting-out field. The numerical analysis module is used to analyze the calculation results of the numerical model and determine the salting-out potential and salting-out current density of the CO2 membrane electrode assembly under operating conditions. The parameter adjustment module is used to adjust various design parameters of the MEA, and determine the most suitable design parameters based on the salting-out situation and the overall performance of the device. The application module is used to suppress salting out by adjusting relevant input parameters at the corresponding salting-out potential.

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