A method for constructing a fuel cell / stack simulation model

Abstract

This invention relates to a method for constructing a fuel cell / stack simulation model, comprising the following steps: Step 1: Constructing an overall model of the fuel cell / stack; Step 2: Implementing the constructed overall model. This invention can improve accuracy and reduce research and development costs.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a method for constructing a fuel cell / stack simulation model. Background Technology

[0002] Fuel cells, in practical operation, are complex nonlinear dynamic systems involving multiple physical domains and multiple input couplings, including fluid mechanics, heat transfer, and electrochemistry. From electrodes to individual cells to the stack, they encompass physicochemical mechanisms at multiple scales, from microscopic to mesoscopic to macroscopic. Accurately describing and controlling the behavior of fuel cells through experiments is extremely challenging. Therefore, modeling and simulating their performance is an intuitive and rapid approach for in-depth research, and the accuracy of the model is crucial for predicting performance during the design and development of fuel cell systems.

[0003] Currently, the main modeling methods for fuel cells / stacks can be categorized as follows:

[0004] a. From the perspective of modeling principles, it can be divided into mechanism model, semi-empirical model, empirical model, equivalent circuit model and data-driven (intelligent) model;

[0005] Among them, the mechanism model is complex to construct and has high computational cost; the semi-empirical model does not fully describe the mechanism; the empirical model lacks description of internal mechanism characteristics and has general accuracy; the equivalent circuit model uses electronic components to simulate actual characteristics and cannot truly reflect the internal mechanism; and the data-driven (intelligent) model requires a large amount of data to support it and cannot analyze the impact of specific internal parameters on the battery.

[0006] b. From the perspective of modeling space dimension, it is divided into one-dimensional model, two-dimensional model and three-dimensional model;

[0007] c. From an object-oriented modeling perspective, it can be divided into distributed parameter models for system design and analysis and lumped parameter models for controller design.

[0008] Distributed parameter models for system design analysis built using modeling and simulation tools are often difficult to use directly for complex controller design, while lumped parameter models for controller design built using ordinary differential equations usually ignore the changes in state distribution inside the fuel cell caused by spatial location. Summary of the Invention

[0009] To address the aforementioned technical problems, the purpose of this invention is to provide a method for constructing a fuel cell / stack simulation model.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A method for constructing a fuel cell / stack simulation model includes the following steps:

[0012] Step 1: Construct an overall model of the fuel cell / stack;

[0013] Step 2: Implement the completed overall model.

[0014] Includes the following steps:

[0015] Step 2.1: Based on the actual physical property parameters of the anode gas and cathode gas in the fuel cell, construct a physical property library for the anode reactant gas and cathode reactant gas;

[0016] Step 2.2: Based on the actual structure, reaction mechanism, and physicochemical performance parameters of the fuel cell / stack, construct simulation models for the anode flow field, individual cells, cathode flow field, and stack temperature.

[0017] Step 2.3: Use the anode / cathode reactive gas property library established in Step 2.1 as the input source term of the anode / cathode flow field simulation model in Step 2.2. The total pressure of the anode / cathode flow field and the pressure of each component gas in the anode / cathode can be obtained by solving the simultaneous equations. The coolant inlet / outlet temperature term obtained by solving the simultaneous equations with the battery temperature simulation model is used as the input term of the single cell simulation model. The operating voltage / power of the fuel cell system is calculated and output by solving the simultaneous equations and debugging and verification are performed.

[0018] Step 2.4: Initialize and run the model after debugging and verification in Step 2.3;

[0019] Step 2.5: Conduct full-condition testing on the actual fuel cell and organize the test data according to the input parameters required by the simulation model for each condition;

[0020] Step 2.6: Input the full-condition experimental data into the initialization model and perform multiple simulation calculations to calibrate and debug the parameters of the controlled model;

[0021] Step 2.7: Determine whether to perform transient operating condition simulation based on actual simulation requirements.

[0022] If so, a dynamic load simulation model of fuel cell current is constructed, and the transient IV performance and battery temperature are simulated and the results are output.

[0023] If not, then perform simulations of steady-state IV performance and battery temperature, and output the results.

[0024] Preferably, in the method for constructing a fuel cell / stack simulation model, the overall model in step 1 includes:

[0025] 1. Establish a fuel gas property library module for the anode / cathode input of the fuel cell. This module establishes a property library of the reactant gas by analyzing the composition, pressure, temperature, flow rate, and mole fraction of each component of the fuel gas for the anode / cathode, which will then be used as input for the subsequent anode / cathode flow field simulation model.

[0026] 2. Establish a cation / cathode flow field simulation model to simulate the cation / cathode and gas diffusion process. This module calculates the cation / cathode gas pressure, flow velocity, consumption and component partial pressure at the flow field outlet by calling relevant parameters from the fuel gas property library and its own volume and flow coefficient parameters.

[0027] 3. Establish a fuel cell temperature management simulation model. This module calculates and outputs the temperature change status of the battery heat generation and loss during the battery operation by inputting the inlet cooling medium flow rate and temperature, battery current and voltage, as well as its own mass and specific heat capacity information.

[0028] 4. Establish a single-cell electrochemical simulation model, and simulate the internal physicochemical state of the fuel cell based on thermodynamics, reaction kinetics, charge transport, mass transport, voltage loss, and polarization curves, and calculate the output operating voltage and power;

[0029] 5. Establish a fuel cell / stack model, combine the models in steps 1 to 4, input the number of individual cells in series and package them into a fuel cell / stack module, apply the load current and calculate the stack output voltage and power.

[0030] Preferably, the method for constructing a fuel cell / stack simulation model, constituting an anode / cathode flow field calculation model, includes the following steps:

[0031] Step 1: Call the anode / cathode reactive gas property library and use the anode / cathode gas flow rate, infeed pressure, molar components of each gas component, and gas temperature as input items for the anode / cathode flow field calculation;

[0032] Step 2: Calculate the mass fraction of each component gas based on the molar component and volume fraction of each component gas, and calculate the mass flow rate of each component gas in the flow field by combining the anode / cathode gas flow rate.

[0033] Step 3: Calculate the consumption rate of each reactant gas based on the results obtained in Step 2, the relative molecular mass of each component gas, and the number of electrons transferred during the reaction process;

[0034] Step 4: Based on the law of conservation of mass and the calculation results obtained in Step 3, the content of each gas component is obtained. Then, combined with the ideal gas law, the partial pressure of each component gas exiting the reactor and the pressure of the anode / cathode gas exiting the reactor can be obtained.

[0035] Step 5: Calculate the anolyte / cathode gas discharge flow rate based on the anolyte / cathode gas discharge pressure obtained in Step 4, the feed pressure in the property library, and the experimentally measured anolyte / cathode flow field flow coefficient.

[0036] Step 6: Based on the partial pressure of each component gas exiting the reactor obtained in Step 4, the flow rate of the anode / cathode gas exiting the reactor obtained in Step 5, and the molar mass of each component gas, the mass flow rate of each component gas outlet can be calculated.

[0037] Preferably, the method for constructing a fuel cell / stack simulation model includes the following steps: Constructing a fuel cell stack temperature calculation model.

[0038] Step 1: Obtain fuel cell mass, average specific heat capacity, and density parameters through actual testing, and collect data on the flow rate and temperature of the cooling medium at the battery / stack inlet using actual sensors;

[0039] Step 2: Calculate the output battery electrochemical reaction power based on the standard molar enthalpy of combustion of hydrogen, the number of battery cells, and the battery current;

[0040] Step 3: Calculate the output power of the battery based on the total battery voltage and current;

[0041] Step 4: Calculate and output the battery's heat generation power based on the battery's electrochemical reaction power and power generation;

[0042] Step 5: Calculate the heat dissipation of the battery coolant based on the coolant flow rate, specific heat capacity, density, and temperature difference between the inlet and outlet of the battery;

[0043] Step 6: Based on the data calculated in Steps 1 to 5, and combined with the heat balance calculation formula, battery specific heat capacity, and mass, calculate the battery outlet coolant temperature.

[0044] Preferably, the method for constructing a fuel cell / stack simulation model is for a simulation model of the operating mechanism of a single fuel cell / stack.

[0045] Includes the following steps:

[0046] Step 1: Obtain the performance parameters of individual cells through actual testing;

[0047] Step 2: Based on the actual structure of the fuel cell, establish a two-dimensional model of a single cell, including the anode / cathode gas diffusion layer, the anode / cathode gas catalyst layer, the anode / cathode electrochemical reaction, and the electrolyte membrane;

[0048] Step 3: Based on chemical thermodynamics and reaction Gibbs free energy, the maximum thermodynamic efficiency of the fuel cell and the thermodynamic efficiency and reaction electromotive force parameters at any temperature can be obtained.

[0049] Step 4: Calculate the output activation overpotential based on the Arrhenius law, Butler-Volmer equation, and Tafel equation, which describe electrochemical reactions and charge transport in reaction kinetics.

[0050] Step 5: Describe the electron transport process in the electrode layer and the ion transport process in the electrolyte membrane according to Arrhenius's law and Ohm's law, and calculate the output Ohm overpotential;

[0051] Step 6: Describe the diffusion and transport process of the reactant gas in the diffusion layer according to Fick's law, the Stefan-Maxwell equation and Faraday's law, calculate the diffusion flux of the diffusion layer components, the reactant concentration at the catalyst inlet and the limiting current density, and further output the concentration overpotential.

[0052] Step 7: Based on Darcy's Law, gas-liquid two-phase transition, diffusion coefficient of hydrogen / oxygen in water, and water content, establish a liquid water transmembrane transport model to simulate the influence of water transport state inside the battery on the polarization curve.

[0053] Step 8: Combine the calculation models obtained from all steps 1 to 7 to obtain the Nernst voltage, activation overpotential, ohmic overpotential, concentration overpotential, number of series-connected cells, input voltage loss of actual load current, actual output voltage, and polarization curve.

[0054] Preferably, the method for constructing a fuel cell / stack simulation model includes the following individual cell performance parameters:

[0055] (1) Thickness, porosity, density, specific heat capacity, electronic conductivity and diffusion coefficient of each gas component of the anode / cathode diffusion layer;

[0056] (2) Thickness, porosity, density, specific heat capacity and electronic / ionic conductivity of the anodic / cathode catalyst layer;

[0057] (3) Activation energy, pre-exponential factor, reaction rate constant, reaction order, and number of exchanged electrons for the cation / cathode electrochemical reaction;

[0058] (4) Electrolyte thickness, porosity, thermal conductivity, ionic conductivity and electronic conductivity.

[0059] Preferably, the method for constructing a fuel cell / stack simulation model is described above.

[0060] For simulations of distributed generation and combined heat and power systems that focus solely on the output voltage characteristics of fuel cells, the modeling of individual cells and the fuel cell stack includes the following steps:

[0061] Step 1: Calculate the ideal open-circuit voltage based on the thermodynamic equations and the Gibbs free energy change at different temperatures;

[0062] Step 2: Calculate the anode activity influence factor based on the anode pressure, hydrogen partial pressure and battery operating temperature; calculate the cathode activity influence factor based on the cathode pressure, oxygen partial pressure and battery operating temperature.

[0063] Step 3: Calculate the battery open-circuit voltage by combining the outputs from Step 1 and Step 2;

[0064] Step 4: Based on Tafel's empirical formula, calculate the cell activation loss voltage by inputting saturated vapor pressure, anode / cathode pressure, hydrogen partial pressure, oxygen partial pressure, stack temperature, and current density.

[0065] Step 5: Based on the empirical formula for ion resistance, calculate the ohmic loss voltage of the battery by inputting the membrane water content, stack temperature, and current density;

[0066] Step 6: Calculate the battery concentration loss voltage based on empirical formulas by inputting current density and concentration loss empirical coefficient;

[0067] Step 7: Calculate the overall battery voltage by combining the outputs from Steps 4 to 6;

[0068] Step 8: Combine Step 3, Step 7, the number of series-connected cells, and the effective active area of ​​a single cell to calculate and output the battery stack voltage, power, and polarization curve.

[0069] By means of the above-described solution, the present invention has at least the following advantages:

[0070] 1. This invention is based on the laws of fuel cell thermodynamics, reaction kinetics, charge transport, and mass transport. By combining mechanistic models, empirical models, and data-driven models, it establishes a complete fuel cell simulation model that includes anode / cathode fuel gas property libraries, anode / cathode flow fields, single cell data, and temperature calculations. This improves the simulation accuracy of fuel cells, accurately reflects the dynamic changes in the internal physicochemical processes of the fuel cell, and enhances the practical value of the model. This addresses the problem that existing fuel cell simulation technologies neglect the characterization of the actual internal reaction mechanisms, ultimately affecting the accuracy of the model.

[0071] 2. This invention is applicable to the simulation and testing development of fuel cells / stacks, BOPs, and systems. It can also be applied to the MIL, SIL, and HIL simulation testing in the fuel cell control development process, greatly reducing the development and debugging cycle and cost of fuel cells and controllers.

[0072] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0073] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0074] Figure 1 This is a schematic diagram of the fuel cell stack model of the present invention;

[0075] Figure 2 This is a flowchart of the fuel cell stack modeling process of the present invention;

[0076] Figure 3 This is a schematic diagram of the fuel cell anode flow field simulation model of the present invention;

[0077] Figure 4 This is a schematic diagram of the fuel cell cathode flow field simulation model of the present invention;

[0078] Figure 5 This is a schematic diagram of the fuel cell temperature calculation simulation model of the present invention;

[0079] Figure 6 This is a schematic diagram of the simulation model of the fuel cell / stack (mechanism) of the present invention;

[0080] Figure 7 These are simulation results and actual curves of the fuel cell stack of this invention;

[0081] Figure 8 This is a schematic diagram of the (empirical) simulation model of the fuel cell unit / stack of the present invention. Detailed Implementation

[0082] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0083] Example 1

[0084] like Figure 1 and Figure 2 As shown, a method for constructing a fuel cell / stack simulation model includes the following steps:

[0085] Step 1: Construct an overall model of the fuel cell / stack.

[0086] The overall model includes:

[0087] 1. Establish a fuel gas property library module for the anode / cathode input of the fuel cell. This module establishes a property library of the reactant gas by collecting information on the composition, pressure, temperature, flow rate, and mole fraction of each component of the fuel gas for the anode / cathode, which will then be used as input for the subsequent anode / cathode flow field simulation model.

[0088] 2. Establish a positive / cathode flow field simulation model to simulate the positive / cathode and gas diffusion process. This module calculates the positive / cathode gas pressure, flow velocity, consumption and component partial pressure at the flow field outlet by calling relevant parameters from the fuel gas property library and its own volume and flow coefficient.

[0089] 3. Establish a fuel cell temperature management simulation model. This module calculates and outputs the temperature change state, such as heat generation and loss of the battery during the internal operation of the battery, by inputting information such as the inlet cooling medium flow rate and temperature, battery current and voltage, as well as its own mass and specific heat capacity.

[0090] 4. Establish a single-cell electrochemical simulation model, and simulate the internal physicochemical state of the fuel cell based on thermodynamics, reaction kinetics, charge transport, mass transport, voltage loss, and polarization curves, and calculate the output operating voltage and power;

[0091] 5. Establish a fuel cell / stack model, combine the models in steps 1 to 4, input the number of individual cells in series and package them into a fuel cell / stack module, apply the load current and calculate the stack output voltage and power;

[0092] Step 2: Implement the completed overall model.

[0093] Includes the following steps:

[0094] Step 2.1: Construct a property library for the anode and cathode gas based on the actual physical properties of the fuel cell anode and cathode gases, such as flow rate, pressure, mass fraction of each component, molar mass, mole fraction, and partial pressure of the gas.

[0095] Step 2.2: Based on the actual structure, reaction mechanism, and physicochemical performance parameters of the fuel cell / stack, construct simulation models for the anode flow field, individual cells, cathode flow field, and stack temperature.

[0096] Step 2.3: Use the anode / cathode reactive gas property library established in Step 2.1 as the input source term of the anode / cathode flow field simulation model in Step 2.2. The total pressure of the anode / cathode flow field and the pressure of each component gas in the anode / cathode can be obtained by solving the simultaneous equations. The coolant inlet / outlet temperature term obtained by solving the simultaneous equations with the battery temperature simulation model is used as the input term of the single cell simulation model. The operating voltage / power of the fuel cell system is calculated and output, and the simultaneous equations are debugged and verified.

[0097] Step 2.4: Initialize and run the model after debugging and verification in Step 2.3;

[0098] Step 2.5: Conduct full-condition testing on the actual fuel cell and organize the test data according to the input parameters required by the simulation model for each condition;

[0099] Step 2.6: Input the full-condition experimental data into the initialization model and perform multiple simulation calculations to calibrate and debug the parameters of the controlled model;

[0100] Step 2.7: Determine whether to perform transient operating condition simulation based on actual simulation requirements.

[0101] If so, a dynamic load simulation model of fuel cell current is constructed, and the transient IV performance and battery temperature are simulated and the results are output.

[0102] If not, then perform simulations of steady-state IV performance and battery temperature, and output the results.

[0103] like Figure 3 and Figure 4 As shown, the calculation model for the anode / cathode flow field is constructed, including the following steps:

[0104] Step 1: Call the anode / cathode reactive gas property library and use the anode / cathode gas flow rate, infeed pressure, molar components of each gas component, and gas temperature as input items for the anode / cathode flow field calculation;

[0105] Step 2: Calculate the mass fraction of each component gas based on the molar component and volume fraction of each component gas, and calculate the mass flow rate of each component gas in the flow field by combining the anode / cathode gas flow rate.

[0106] Step 3: Calculate the consumption rate of each reactant gas based on the results obtained in Step 2, the relative molecular mass of each component gas, and the number of electrons transferred during the reaction process;

[0107] Step 4: Based on the law of conservation of mass and the calculation results obtained in Step 3, the content of each gas component is obtained. Then, combined with the ideal gas law, the partial pressure of each component gas exiting the reactor and the pressure of the anode / cathode gas exiting the reactor can be obtained.

[0108] Step 5: Calculate the anolyte / cathode gas discharge flow rate based on the anolyte / cathode gas discharge pressure obtained in Step 4, the feed pressure in the property library, and the experimentally measured anolyte / cathode flow field flow coefficient.

[0109] Step 6: Based on the partial pressure of each component gas exiting the reactor obtained in Step 4, the flow rate of the anode / cathode gas exiting the reactor obtained in Step 5, and the molar mass of each component gas, the mass flow rate of each component gas outlet can be calculated.

[0110] Combining the relevant algorithms in steps 1-6 of the anode / cathode flow field calculation model, the anode / cathode flow field calculation model is built. The simultaneous equations are solved to calculate and output the total pressure of the anode / cathode flow field, the partial pressure of each component gas, the gas flow rate, the reaction consumption, etc., as inputs to the battery calculation model.

[0111] like Figure 5 As shown, the battery stack temperature calculation model is constructed, including the following steps:

[0112] Step 1: Obtain physical property parameters such as fuel cell mass, average specific heat capacity, and density through actual testing, and collect data such as the flow rate and temperature of the cooling medium at the battery / stack inlet through actual sensors;

[0113] Step 2: Calculate the output battery electrochemical reaction power based on the standard molar enthalpy of combustion of hydrogen, the number of battery cells, and the battery current;

[0114] Step 3: Calculate the output power of the battery based on the total battery voltage, current, etc.

[0115] Step 4: Calculate and output the battery's heat generation power based on the battery's electrochemical reaction power and power generation;

[0116] Step 5: Calculate the heat dissipation of the battery coolant based on the coolant flow rate, specific heat capacity, density, and temperature difference between the inlet and outlet of the battery;

[0117] Step 6: Based on the data obtained from Steps 1 to 5, and combined with the heat balance calculation formula and the battery's specific heat capacity and mass, calculate the battery outlet coolant temperature.

[0118] like Figure 6 As shown, the simulation model for the operating mechanism of a single fuel cell / stack includes the following steps:

[0119] Step 1: Obtain the performance parameters of individual cells through actual testing;

[0120] (1) Thickness, porosity, density, specific heat capacity, electronic conductivity, and diffusion coefficient of each gas component of the anode / cathode diffusion layer;

[0121] (2) Thickness, porosity, density, specific heat capacity, and electronic / ionic conductivity of the anodic / cathode catalyst layer;

[0122] (3) Activation energy, pre-exponential factor, reaction rate constant, reaction order, and number of exchanged electrons for the cation / cathode (hydrogen / oxygen) electrochemical reaction;

[0123] (4) Electrolyte thickness, porosity, thermal conductivity, ionic conductivity, electronic conductivity, etc.

[0124] Step 2: Based on the actual structure of the fuel cell, establish a two-dimensional model of a single cell, including the anode / cathode gas diffusion layer, the anode / cathode gas catalyst layer, the anode / cathode electrochemical reaction, and the electrolyte membrane;

[0125] Step 3: Based on chemical thermodynamics and reaction Gibbs free energy, the maximum thermodynamic efficiency of the fuel cell and parameters such as the thermodynamic efficiency and reaction electromotive force at any temperature can be obtained;

[0126] Step 4: Calculate the output activation overpotential based on the Arrhenius law, Butler-Volmer equation, Tafel equation, etc., which describe electrochemical reactions and charge transport in reaction kinetics;

[0127] Step 5: Describe the processes of electron transport in the electrode layer and ion transport in the electrolyte membrane according to Arrhenius's law and Ohm's law, and calculate the output ohmic overpotential;

[0128] Step 6: Describe the diffusion and transport process of the reactant gas in the diffusion layer according to Fick's law, the Stefan-Maxwell equation and Faraday's law, calculate the diffusion flux of the diffusion layer components, the reactant concentration at the catalyst inlet and the limiting current density, and further output the concentration overpotential.

[0129] Step 7: Based on Darcy's Law, gas-liquid two-phase transition, diffusion coefficient of hydrogen / oxygen in water, water content, etc., establish a liquid water transmembrane transport model to simulate the influence of water transport state inside the battery on the polarization curve.

[0130] Step 8: Combine the calculation models obtained from all steps 1 to 7 to calculate the Nernst voltage, activation overpotential, ohmic overpotential, concentration overpotential, etc., as well as the number of series-connected cells, the actual input load current, etc., to calculate the voltage loss, actual output voltage, and polarization curve.

[0131] By comparing and analyzing the measured data with that of a real fuel cell power model, it can be verified that the overall accuracy of this model is over 97%. Specific comparative analysis is as follows: Figure 7 As shown.

[0132] Example 2

[0133] Based on the above embodiments, for some large-scale fuel cell-based systems, such as distributed generation and combined heat and power systems, where the economic simulation analysis only focuses on the fuel cell output voltage characteristics and not its internal operating mechanism, the modeling of individual cells can be done using methods such as... Figure 8 The empirical model shown includes open-circuit voltage calculation and overall voltage drop calculation, specifically comprising the following steps:

[0134] Step 1: Calculate the ideal open-circuit voltage based on the thermodynamic equations and the Gibbs free energy change at different temperatures;

[0135] Step 2: Calculate the anode activity influence factor based on the anode pressure, hydrogen partial pressure and battery operating temperature; calculate the cathode activity influence factor based on the cathode pressure, oxygen partial pressure and battery operating temperature.

[0136] Step 3: Calculate the battery open-circuit voltage by combining the outputs from Step 1 and Step 2;

[0137] Step 4: Based on Tafel's empirical formula, calculate the cell activation loss voltage by inputting saturated vapor pressure, anode / cathode pressure, hydrogen partial pressure, oxygen partial pressure, stack temperature, current density, etc.

[0138] Step 5: Based on the empirical formula for ion resistance, calculate the ohmic loss voltage of the battery by inputting the membrane water content, stack temperature, current density, etc.

[0139] Step 6: Calculate the battery concentration loss voltage based on empirical formulas, by inputting current density, concentration loss empirical coefficient, etc.

[0140] Step 7: Calculate the overall battery voltage drop by combining the outputs from Steps 4 to 6.

[0141] Step 8: Combining Step 3 and Step 7, as well as the number of series-connected cells and the effective active area of ​​individual cells, calculate and output the battery stack voltage, power, and polarization curve.

[0142] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0143] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0144] In the description of this application, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0145] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or vertical, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0146] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0147] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for constructing a fuel cell simulation model, characterized in that, Includes the following steps: Step 1: Construct an overall model of the fuel cell; Step 2: Implement the completed overall model. Includes the following steps: Step 2.1: Based on the actual physical property parameters of the anode gas and cathode gas in the fuel cell, construct a physical property library for the anode reactant gas and cathode reactant gas; Step 2.2: Based on the actual structure, reaction mechanism, and physicochemical performance parameters of the fuel cell, construct simulation models for the anode flow field, single cell, cathode flow field, and cell temperature. Step 2.3: Use the anode / cathode reactive gas property library established in Step 2.1 as the input source term of the anode / cathode flow field simulation model in Step 2.

2. The total pressure of the anode / cathode flow field and the pressure of each component gas in the anode / cathode can be obtained by solving the simultaneous equations. The coolant inlet / outlet temperature term obtained by solving the simultaneous equations with the battery temperature simulation model is used as the input term of the single cell simulation model. The operating voltage / power of the fuel cell system is calculated and output by solving the simultaneous equations and debugging and verification are performed. Step 2.4: Initialize and run the model after debugging and verification in Step 2.3; Step 2.5: Conduct full-condition testing on the actual fuel cell and organize the test data according to the input parameters required by the simulation model for each condition; Step 2.6: Input the full-condition experimental data into the initialization model and perform multiple simulation calculations to calibrate and debug the parameters of the controlled model; Step 2.7: Determine whether to perform transient operating condition simulation based on actual simulation requirements. If so, a dynamic load simulation model of fuel cell current is constructed, and the transient IV performance and battery temperature are simulated and the results are output. If not, then perform simulations of steady-state IV performance and battery temperature, and output the results. The overall model in step 1 includes: 1) Establish a fuel gas property library module for the anode / cathode of the fuel cell. This module establishes a property library of the reactant gas by analyzing the composition, pressure, temperature, flow rate, and mole fraction of each component of the fuel gas for the anode / cathode, which will then be used as input for the subsequent anode / cathode flow field simulation model. 2) Establish a positive / cathode flow field simulation model to simulate the positive / cathode and gas diffusion process. This module calculates the positive / cathode gas pressure, flow velocity, consumption and component partial pressure at the flow field outlet by calling relevant parameters from the fuel gas property library and its own volume and flow coefficient parameters. 3) Establish a fuel cell temperature management simulation model. This module calculates and outputs the temperature change status of the battery heat generation and loss during the battery operation by inputting the inlet cooling medium flow rate and temperature, battery current and voltage, as well as its own mass and specific heat capacity information. 4) Establish a single-cell electrochemical simulation model, and simulate the internal physicochemical state of the fuel cell based on thermodynamics, reaction kinetics, charge transport, mass transport, voltage loss and polarization curves, and calculate the output operating voltage and power; 5) Establish a fuel cell model, combine the models in 1) to 4) and input the number of series-connected individual cells to package them into a fuel cell module, apply the load current and calculate the stack output voltage and power; Constructing a cation / cathode flow field calculation model includes the following steps: Step 1: Call the anode / cathode reactive gas property library and use the anode / cathode gas flow rate, infeed pressure, molar components of each gas component, and gas temperature as input items for the anode / cathode flow field calculation; Step 2: Calculate the mass fraction of each component gas based on the molar component and volume fraction of each component gas, and calculate the mass flow rate of each component gas in the flow field by combining the anode / cathode gas flow rate. Step 3: Calculate the consumption rate of each reactant gas based on the results obtained in Step 2, the relative molecular mass of each component gas, and the number of electrons transferred during the reaction process; Step 4: Based on the law of conservation of mass and the calculation results obtained in Step 3, the content of each gas component is obtained. Then, combined with the ideal gas law, the partial pressure of each component gas exiting the reactor and the pressure of the anode / cathode gas exiting the reactor can be obtained. Step 5: Calculate the anolyte / cathode gas discharge flow rate based on the anolyte / cathode gas discharge pressure obtained in Step 4, the feed pressure in the property library, and the experimentally measured anolyte / cathode flow field flow coefficient. Step 6: Based on the partial pressure of each component gas exiting the stack obtained in Step 4, the flow rate of the anode / cathode gas exiting the stack obtained in Step 5, and the molar mass of each component gas, the outlet mass flow rate of each component gas can be calculated. Constructing a battery temperature calculation model includes the following steps: Step 1: Obtain fuel cell mass, average specific heat capacity, and density parameters through actual testing, and collect data on the flow rate and temperature of the cooling medium at the battery inlet using actual sensors; Step 2: Calculate the output battery electrochemical reaction power based on the standard molar enthalpy of combustion of hydrogen, the number of battery cells, and the battery current; Step 3: Calculate the output power of the battery based on the total battery voltage and current; Step 4: Calculate and output the battery's heat generation power based on the battery's electrochemical reaction power and power generation; Step 5: Calculate the heat dissipation of the battery coolant based on the coolant flow rate, specific heat capacity, density, and temperature difference between the inlet and outlet of the battery; Step 6: Based on the data calculated in Steps 1 to 5, and combined with the heat balance calculation formula, battery specific heat capacity, and mass, calculate the battery outlet coolant temperature. For the simulation model of the operating mechanism of a single fuel cell, Includes the following steps: Step 1: Obtain the performance parameters of individual cells through actual testing; Step 2: Based on the actual structure of the fuel cell, establish a two-dimensional model of a single cell, including the anode / cathode gas diffusion layer, the anode / cathode gas catalyst layer, the anode / cathode electrochemical reaction, and the electrolyte membrane; Step 3: Based on chemical thermodynamics and reaction Gibbs free energy, the maximum thermodynamic efficiency of the fuel cell and the thermodynamic efficiency and reaction electromotive force parameters at any temperature can be obtained. Step 4: Calculate the output activation overpotential based on the Arenius law, Butler-Wolmer equation, and Tafel equation, which describe electrochemical reactions and charge transport in reaction kinetics. Step 5: Describe the electron transport process in the electrode layer and the ion transport process in the electrolyte membrane according to Arenius's law and Ohm's law, and calculate the output Ohm overpotential; Step 6: Describe the diffusion and transport process of the reactant gas in the diffusion layer according to Fick's law, the Stephen-Maxwell equation and Faraday's law, calculate the diffusion flux of the diffusion layer components, the reactant concentration at the catalyst inlet and the limiting current density, and further output the concentration overpotential. Step 7: Based on Darcy's law, gas-liquid two-phase transition, diffusion coefficient of hydrogen / oxygen in water, and water content, establish a liquid water transmembrane transport model to simulate the influence of water transport state inside the battery on the polarization curve. Step 8: Combine the calculation models obtained from all steps 1 to 7 to obtain the Nernst voltage, activation overpotential, ohmic overpotential, concentration overpotential, number of series-connected cells, input voltage loss of actual load current, actual output voltage, and polarization curve.

2. The method for constructing a fuel cell simulation model according to claim 1, characterized in that: The performance parameters of a single battery cell include: (1) Thickness, porosity, density, specific heat capacity, electronic conductivity and diffusion coefficient of each gas component of the anode / cathode diffusion layer; (2) Thickness, porosity, density, specific heat capacity and electronic / ionic conductivity of the anodic / cathode catalyst layer; (3) Activation energy, pre-exponential factor, reaction rate constant, reaction order, and number of exchanged electrons for the cation / cathode electrochemical reaction; (4) Electrolyte thickness, porosity, thermal conductivity, ionic conductivity and electronic conductivity.

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