A three-dimensional simulation method and system for diffusion of dissolved hydrogen in an alkaline electrolyzer

Abstract

This invention discloses a three-dimensional simulation method and system for dissolved hydrogen diffusion in an alkaline electrolyzer, belonging to the field of electrolyzer simulation calculation technology. The method includes: establishing a three-dimensional geometric model of an alkaline electrolyzer unit comprising bipolar plates, flow channels, electrodes, and a diaphragm; constructing a dynamic equilibrium module for dissolved hydrogen coupled with the hydrogen dissolution and evolution processes; constructing a diffusion simulation module including concentration diffusion, convection diffusion, and electroosmotic diffusion mechanisms; constructing a dynamic upper limit control model for dissolved hydrogen concentration, dynamically selecting the actual dissolved hydrogen concentration; coupling the determined actual dissolved hydrogen concentration to the diffusion simulation module to obtain the concentration distribution of dissolved hydrogen in the electrolyzer, and outputting simulation results including HTO based on the concentration distribution. This invention improves the prediction accuracy of HTO under low current density conditions by introducing a dynamic upper limit control mechanism for dissolved hydrogen concentration, simultaneously considering the dual constraints of generation rate limitations at low current densities and oversaturation limitations at medium to high current densities.

Description

Technical Field

[0001] This invention relates to the field of alkaline electrolytic cell simulation calculation technology, specifically a three-dimensional simulation method and system for the diffusion of dissolved hydrogen in an alkaline electrolytic cell. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is currently the most widely used large-scale green hydrogen production technology. It achieves zero-carbon hydrogen production by driving water splitting with renewable energy electricity. However, under low current density conditions, the hydrogen volume fraction (HTO) in the oxygen at the anode side increases significantly. When the HTO exceeds the safety threshold (typically 2%), the system must be shut down immediately to prevent the formation of an explosive mixture. This severely restricts the operating load range of the electrolyzer, especially when coupled with fluctuating renewable energy power. Frequent start-ups and shutdowns or operation in low-load ranges significantly increase the risk of HTO exceeding limits, becoming a core bottleneck restricting the safe and stable operation of the system.

[0003] In-depth analysis reveals that the fundamental reason for the increase in HTO lies in the diffusion and migration of dissolved hydrogen generated during electrolysis from the cathode side to the anode side through the diaphragm. Therefore, accurately simulating the diffusion behavior of dissolved hydrogen within the electrolyzer is of great significance for predicting HTO variation patterns and guiding the optimization of electrolyzer structure and the formulation of operating strategies.

[0004] However, existing simulation modeling methods often neglect the supersaturation of dissolved hydrogen at the electrode-membrane interface when describing the diffusion behavior of dissolved hydrogen, simply limiting the dissolved hydrogen concentration to the saturated solubility under thermodynamic equilibrium conditions. This leads to an underestimation of the dissolved hydrogen concentration at high current densities. Moreover, under low current density conditions, due to the low hydrogen generation rate, the actual concentration of dissolved hydrogen often fails to reach the saturated solubility; its concentration is mainly limited by the generation rate rather than the dissolving capacity, and existing models fail to consider this generation rate limiting mechanism. The neglect of these factors results in significant deviations in the prediction of dissolved hydrogen concentration distribution and transmembrane diffusion flux over a wide load range, especially under low current density conditions. This makes it difficult to accurately assess the changing trend of HTO and to provide a reliable basis for defining the safe operating range and optimizing the structure of the electrolyzer. Summary of the Invention

[0005] The purpose of this invention is to provide a three-dimensional simulation method and system for the diffusion of dissolved hydrogen in an alkaline electrolyzer, in order to solve the above-mentioned problems.

[0006] The technical solution of this invention is: A three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolyzer, used to improve the prediction accuracy of gas purity (HTO) under low current density conditions, includes the following steps: A three-dimensional geometric model of an alkaline electrolyzer unit, including bipolar plates, flow channels, electrodes, and a diaphragm, is established. Based on a three-dimensional geometric model, a dynamic equilibrium module for dissolved hydrogen, a diffusion simulation module, and a dynamic upper limit module for dissolved hydrogen concentration are constructed. The domain of the dynamic upper limit module for dissolved hydrogen concentration is set within the cathode-side electrode and the flow channel; the domain of the diffusion simulation module is set within the diaphragm, the anode-side electrode, and the flow channel. The dynamic equilibrium module for dissolved hydrogen is used to calculate the dissolved hydrogen generation rate and input the dissolved hydrogen generation rate into the diffusion simulation module; the dynamic upper limit module for dissolved hydrogen concentration is used to determine the upper limit value of the actual dissolved hydrogen concentration and couples it as a constraint condition to the diffusion simulation module; under the joint constraint of the dissolved hydrogen generation rate and the upper limit value of the actual dissolved hydrogen concentration, the diffusion simulation module solves for the concentration distribution of dissolved hydrogen in the electrolyzer and outputs simulation results including HTO based on the concentration distribution. The dynamic upper limit module for dissolved hydrogen concentration includes the following control steps: Based on local current density Real-time calculation of the concentration limiting the rate of dissolved hydrogen formation and supersaturation limit concentration The supersaturation limit concentration Based on the supersaturation increment term related to theoretical solubility and current density Calculated; by comparing the generation rate-limited concentration With the supersaturation limit concentration The size of the actual dissolved hydrogen concentration is dynamically selected. Upper limit: When the concentration limiting the generation rate is less than the supersaturation limit concentration, it is determined to be a low current density operating condition, and the concentration limiting the generation rate is taken as the actual concentration. When the concentration limiting the generation rate is greater than the supersaturation limit concentration, it is determined to be a medium-to-high current density operating condition, and the supersaturation limit concentration is used as the actual concentration.

[0007] Furthermore, the formula for calculating the supersaturation limit concentration is as follows: ; in, For theoretical solubility, For local current density, It is Faraday's constant. Let be the mass transfer coefficient of the two-film theory; the formula for calculating the mass transfer coefficient of the two-film theory is: ;in, The prefactor of the mass transfer coefficient; The pressure of the fluid; The formula for calculating the theoretical solubility is as follows: ; in, , and Indicates the solubility of dissolved gases, Coefficients and corresponding partial pressures.

[0008] Furthermore, the generation rate limiting concentration The calculation formula is: ; in, and These represent the number of participating electrons in the half-electrode reaction and the stoichiometric coefficient of hydrogen, respectively. denoted as the volume current density of the electrode.

[0009] Furthermore, the domain of action of the dissolved hydrogen dynamic equilibrium module is set within the flow channel, diaphragm, and electrode, and its equilibrium equation is constructed based on the two-film mass transfer theory as follows: ; in, This indicates the output of hydrogen through electrolysis. This indicates the mass transfer of dissolved hydrogen to the gaseous state; This represents the transmembrane mass transfer of dissolved hydrogen, which accounts for a very small percentage and can be ignored.

[0010] Furthermore, the governing equation for the concentration diffusion submodule is: ; in, This represents the mass flux of dissolved hydrogen transferred through concentration diffusion; It is the effective diffusion coefficient of dissolved hydrogen; The concentration gradient of dissolved hydrogen is represented by the following formula: ; in, Here is the reference diffusion coefficient of dissolved hydrogen in KOH solution at the reference temperature; The activation energy is the dissolved hydrogen in the KOH solution. This is the current temperature; This is a reference temperature.

[0011] Furthermore, the governing equations for the convection-diffusion submodule are as follows: ; in, This represents the mass flux of dissolved hydrogen transferred through convection and diffusion. The fluid velocity; This represents the concentration of dissolved hydrogen.

[0012] Furthermore, the calculation equation for the electroosmotic diffusion submodule is as follows: ; in, This represents the mass flux of dissolved hydrogen transferred via electroosmosis diffusion; This represents the solubility of hydrogen. This is the electroosmotic drag coefficient.

[0013] Furthermore, the overall mass diffusion equation of the diffusion simulation module is: ; in, The source term of the mass diffusion equation is: .

[0014] Furthermore, the domain of the dynamic upper limit module for dissolved hydrogen concentration is set within the cathode-side electrode and the flow channel; the domain of the diffusion simulation module is set within the diaphragm, the anode-side electrode, and the flow channel.

[0015] A three-dimensional simulation system for the diffusion of dissolved hydrogen in an alkaline electrolyzer, used to execute the above-mentioned three-dimensional simulation method, includes: A three-dimensional geometric model module, comprising: an alkaline electrolytic cell unit consisting of bipolar plates, flow channels, electrodes, and a diaphragm; The dissolved hydrogen dynamic equilibrium module interacts with the three-dimensional geometric model module to simulate the dissolution mass transfer of electrolyzed hydrogen in KOH solution based on the three-dimensional geometric model, as well as the precipitation transfer calculation when dissolved hydrogen reaches supersaturation solubility. The diffusion simulation module interacts with the three-dimensional geometric model module and the dissolved hydrogen dynamic equilibrium module to calculate the concentration diffusion flux, convection diffusion flux and electroosmotic diffusion flux of dissolved hydrogen in the electrolyzer based on the three-dimensional geometric model, so as to simulate the diffusion and transfer process of dissolved hydrogen in the electrolyzer. The dynamic upper limit module for dissolved hydrogen concentration interacts with the three-dimensional geometric model module to dynamically correct the upper limit of dissolved hydrogen concentration based on the three-dimensional geometric model and operating conditions. The dynamic upper limit module for dissolved hydrogen concentration includes a supersaturated solubility calculation unit. The supersaturated solubility calculation unit determines the theoretical solubility based on temperature, pressure and KOH solution concentration, and performs supersaturation correction on the theoretical solubility based on current density to construct the supersaturation limit concentration of dissolved hydrogen. The simulation construction module is connected to the dissolved hydrogen dynamic equilibrium module, the diffusion simulation module, and the dissolved hydrogen concentration dynamic upper limit module, respectively. It is used to associate the interaction information of each module and couple the supersaturation limit concentration determined by the dissolved hydrogen concentration dynamic upper limit module to the diffusion simulation module to construct a three-dimensional simulation model of dissolved hydrogen diffusion in the alkaline electrolyzer.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a precise spatial characterization basis for studying the transmembrane diffusion behavior of dissolved hydrogen by establishing a complete three-dimensional geometric model of an electrolyzer unit including bipolar plates, flow channels, electrodes, and a diaphragm. Based on this, a complete physical description framework for the generation, precipitation, and migration behavior of dissolved hydrogen in the electrolyte is formed by constructing a dynamic equilibrium sub-model of dissolved hydrogen coupled with the hydrogen dissolution and precipitation processes, and a dissolved hydrogen diffusion simulation sub-model covering three mechanisms: concentration diffusion, convection diffusion, and electroosmotic diffusion. A dynamic upper limit control model for dissolved hydrogen concentration is constructed. This model calculates the generation rate limit concentration and the supersaturation limit concentration in real time based on local current density, and dynamically selects the actual dissolved hydrogen concentration by comparing their magnitudes: at low current densities, the generation rate limit concentration is used as the actual concentration, accurately reflecting the constraint of the gas production rate on the concentration; at medium to high current densities, the supersaturation limit concentration is used as the actual concentration, effectively characterizing the upper limit of concentration imposed by the supersaturation phenomenon. Coupled with this dynamically determined actual concentration to the diffusion simulation sub-model for solution, the calculation of dissolved hydrogen concentration distribution simultaneously considers both physical mechanisms. This study achieves refined simulation of the multi-mechanism coupling of dissolved hydrogen in the electrolyzer, significantly improving the calculation accuracy of dissolved hydrogen concentration distribution and transmembrane diffusion flux over a wide load range, especially under low current density conditions. This makes the prediction results of HTO, a key safety indicator, closer to physical reality, providing reliable numerical simulation support for defining the safe operating range of the electrolyzer, optimizing its structure, and formulating operating strategies. Attached Figure Description

[0017] Figure 1 This is a flowchart of the three-dimensional simulation method of the present invention.

[0018] Figure 2 This is a flowchart of the dynamic upper limit module for dissolved hydrogen concentration of the present invention.

[0019] Figure 3 This is a schematic diagram of the three-dimensional simulation results of the present invention. Detailed Implementation

[0020] The following is combined Figures 1 to 3 The specific embodiments of the present invention will be described in detail below.

[0021] It should be noted that the communication circuit connections between modules involved in this invention all adopt conventional circuit connection methods and do not involve any innovation.

[0022] Example like Figure 1 As shown, a three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolyzer is used to improve the prediction accuracy of gas purity (HTO) under low current density conditions. The method includes the following steps: A three-dimensional geometric model of an alkaline electrolyzer unit, including bipolar plates, flow channels, electrodes, and a diaphragm, was established. This model characterizes the core structural components of the electrolyzer, providing a spatial basis for subsequent physical field simulations. The flow channel structure was modeled based on the actual electrolyzer design, and the geometric parameters such as the thickness and porosity of the electrodes and diaphragm were set according to their actual physical dimensions.

[0023] A dynamic equilibrium module for dissolved hydrogen was constructed to describe the dynamic equilibrium relationship between hydrogen dissolution and precipitation. Its domain was set in the flow channel, diaphragm and electrode. Its equilibrium equation, based on the two-film mass transfer theory, is constructed as follows: ; in, This indicates the output of hydrogen through electrolysis. This indicates the mass transfer of dissolved hydrogen to the gaseous state; This represents the transmembrane mass transfer of dissolved hydrogen, which accounts for a very small percentage and can be ignored.

[0024] A diffusion simulation module based on the theory of material diffusion is constructed. The diffusion simulation module includes a concentration diffusion submodule, a convection diffusion submodule, and an electroosmotic diffusion submodule. The domain of the diffusion simulation module is set at the diaphragm, the anode side electrode, and the flow channel.

[0025] The governing equations for the concentration diffusion submodule are: ; in, This represents the mass flux of dissolved hydrogen transferred through concentration diffusion; It is the effective diffusion coefficient of dissolved hydrogen; The concentration gradient of dissolved hydrogen is represented by the following formula: The effective diffusion coefficient of dissolved hydrogen is calculated as follows: ; in, The reference diffusion coefficient for dissolved hydrogen in KOH solution at a reference temperature of 80℃ is given. The activation energy is the dissolved hydrogen in the KOH solution. This is the current temperature; This is the reference temperature, which is 80℃.

[0026] The governing equations for the convection-diffusion submodule are: ; in, This represents the mass flux of dissolved hydrogen transferred through convection and diffusion. The fluid velocity; This represents the concentration of dissolved hydrogen.

[0027] The calculation equations for the electroosmotic diffusion submodule are as follows: ; in, This represents the mass flux of dissolved hydrogen transferred via electroosmosis diffusion; This represents the solubility of hydrogen. This is the electroosmotic drag coefficient.

[0028] Combining the three diffusion mechanisms mentioned above, the overall mass diffusion equation for the diffusion simulation module is: ; in, The source term of the mass diffusion equation is: .

[0029] A dynamic upper limit module for dissolved hydrogen concentration is constructed to dynamically adjust the upper limit of dissolved hydrogen concentration based on operating conditions. The scope of this module is set within the cathode-side electrode and the flow channel. Figure 2 As shown, the dynamic upper limit module for dissolved hydrogen concentration includes the following control steps: Based on local current density Real-time calculation of the concentration limiting the rate of dissolved hydrogen formation and supersaturation limit concentration The supersaturation limit concentration Based on the supersaturation increment term related to theoretical solubility and current density Calculated; concentration limited by generation rate. With supersaturation limit concentration The size of the actual dissolved hydrogen concentration is dynamically selected. Upper limit: Under low current density conditions, when the generation rate limits the concentration concentration below the supersaturation limit Then, the generation rate limiting concentration is selected as the actual dissolved hydrogen concentration; under medium-high current density conditions, when the generation rate limiting concentration... concentrations above the supersaturation limit The supersaturation limit concentration is then selected as the actual dissolved hydrogen concentration. The low current density and medium-high current density are not based on fixed values, but are dynamically defined according to the relative magnitudes of the dissolved hydrogen generation rate limit concentration and the supersaturation limit concentration. When the concentration limiting the generation rate is less than the supersaturation limit concentration, it is automatically determined to be a low current density operating condition. When the concentration limiting the generation rate is greater than the supersaturation limit concentration, it is automatically determined to be a medium-to-high current density operating condition.

[0030] Local current density In electrolytic cell simulation and CFD calculation, it is a standard term referring to the current density at a tiny location on the electrode surface.

[0031] The theoretical solubility of dissolved hydrogen is calculated based on Henry's Law: ; in, , and Indicates the solubility of dissolved gases, Coefficients and corresponding partial pressures.

[0032] There is a local supersaturation of dissolved hydrogen at the junction of the cathode and diaphragm, which makes the local concentration gradient greater than the theoretical concentration gradient.

[0033] Considering the localized supersaturation of dissolved hydrogen at the cathode-diaphragm interface, which causes the local concentration gradient to exceed the theoretical concentration gradient, a supersaturation correction is needed for the theoretical solubility. The formula for calculating the supersaturation limit concentration is: ;

[0034] in, For theoretical solubility, For local current density, It is Faraday's constant. Let be the mass transfer coefficient of the two-film theory; the formula for calculating the mass transfer coefficient of the two-film theory is: ;in, The prefactor of the mass transfer coefficient; The pressure of the fluid; Assuming all the hydrogen produced by electrolysis exists in dissolved form, the formula for calculating the rate-limiting concentration of dissolved hydrogen production is: ; in, and These represent the number of participating electrons in the half-electrode reaction and the stoichiometric coefficient of hydrogen, respectively. denoted as the volume current density of the electrode.

[0035] The determined actual dissolved hydrogen concentration is coupled to the diffusion simulation module and substituted into the overall mass diffusion equation for solution, yielding the dissolved hydrogen concentration distribution within the electrolyzer. By integrating the dissolved hydrogen dynamic equilibrium module, the diffusion simulation module, and the dissolved hydrogen concentration dynamic upper limit module into a three-dimensional geometric model, a complete three-dimensional simulation model of dissolved hydrogen diffusion within the alkaline electrolyzer is constructed. Based on the solved dissolved hydrogen concentration distribution, the transmembrane diffusion flux is further calculated, and the final simulation results, including HTO, are output.

[0036] like Figure 3As shown, the simulation method in this embodiment can more accurately predict the concentration distribution of dissolved hydrogen and the HTO variation pattern over a wide load range, especially under low current density conditions.

[0037] A three-dimensional simulation system for dissolved hydrogen diffusion in an alkaline electrolyzer, used to execute the above-mentioned three-dimensional simulation method, includes: a three-dimensional geometric model module, a dissolved hydrogen dynamic equilibrium module, a diffusion simulation module, a dissolved hydrogen concentration dynamic upper limit module, and a simulation construction module; The three-dimensional geometric model module includes an alkaline electrolytic cell unit consisting of bipolar plates, flow channels, electrodes, and a diaphragm. The dissolved hydrogen dynamic equilibrium module is connected to the three-dimensional geometric model module. It is used to simulate the mass transfer of dissolved hydrogen in KOH solution based on the three-dimensional geometric model, as well as the precipitation transfer calculation when dissolved hydrogen reaches supersaturation solubility. The diffusion simulation module interacts with the three-dimensional geometric model module and the dissolved hydrogen dynamic equilibrium module to calculate the concentration diffusion flux, convection diffusion flux and electroosmotic diffusion flux of dissolved hydrogen in the electrolyzer based on the three-dimensional geometric model, so as to simulate the diffusion and transfer process of dissolved hydrogen in the electrolyzer. The dynamic upper limit module for dissolved hydrogen concentration is connected to the three-dimensional geometric model module. It is used to dynamically correct the upper limit of dissolved hydrogen concentration based on the three-dimensional geometric model and according to the working conditions. The dynamic upper limit module for dissolved hydrogen concentration includes a supersaturated solubility calculation unit. The supersaturated solubility calculation unit determines the theoretical solubility based on temperature, pressure and KOH solution concentration, and performs supersaturation correction on the theoretical solubility based on current density to construct the supersaturation limit concentration of dissolved hydrogen. The simulation construction module is connected to the dissolved hydrogen dynamic equilibrium module, the diffusion simulation module, and the dissolved hydrogen concentration dynamic upper limit module, respectively, to associate the interaction information of each module. The supersaturation limit concentration determined by the dissolved hydrogen concentration dynamic upper limit module is coupled to the diffusion simulation module to construct a three-dimensional simulation model of dissolved hydrogen diffusion in the alkaline electrolyzer.

[0038] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolyzer, characterized in that, Includes the following steps: A three-dimensional geometric model of an alkaline electrolyzer unit, including bipolar plates, flow channels, electrodes, and a diaphragm, is established. Based on a three-dimensional geometric model, a dynamic equilibrium module for dissolved hydrogen, a diffusion simulation module, and a dynamic upper limit module for dissolved hydrogen concentration are constructed. The domain of the dynamic upper limit module for dissolved hydrogen concentration is set within the cathode-side electrode and the flow channel; the domain of the diffusion simulation module is set within the diaphragm, the anode-side electrode, and the flow channel; the dynamic equilibrium module for dissolved hydrogen is used to calculate the dissolved hydrogen generation rate and input the dissolved hydrogen generation rate into the diffusion simulation module; the dynamic upper limit module for dissolved hydrogen concentration is used to determine the actual upper limit value of dissolved hydrogen concentration and couples it as a constraint condition to the diffusion simulation module. Under the combined constraints of the dissolved hydrogen generation rate and the upper limit of the actual dissolved hydrogen concentration, the diffusion simulation module solves for the concentration distribution of dissolved hydrogen in the electrolyzer and outputs simulation results including HTO based on the concentration distribution. The dynamic upper limit module for dissolved hydrogen concentration includes the following control steps: Based on local current density Real-time calculation of the concentration limiting the rate of dissolved hydrogen formation and supersaturation limit concentration The supersaturation limit concentration Based on the supersaturation increment term related to theoretical solubility and current density Calculated; by comparing the generation rate-limited concentration With the supersaturation limit concentration The size of the actual dissolved hydrogen concentration is dynamically selected. Upper limit: When the concentration limiting the generation rate is less than the supersaturation limit concentration, it is determined to be a low current density operating condition, and the concentration limiting the generation rate is taken as the actual concentration. When the concentration limiting the generation rate is greater than the supersaturation limit concentration, it is determined to be a medium-to-high current density operating condition, and the supersaturation limit concentration is used as the actual concentration.

2. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 1, characterized in that, The formula for calculating the supersaturation limit concentration is as follows: ; in, For theoretical solubility, For local current density, It is Faraday's constant. Let be the mass transfer coefficient of the two-film theory; the formula for calculating the mass transfer coefficient of the two-film theory is: ;in, The prefactor of the mass transfer coefficient; The pressure of the fluid; The formula for calculating the theoretical solubility is as follows: ; in, , and Indicates the solubility of dissolved gases, Coefficients and corresponding partial pressures.

3. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolyzer according to claim 1, characterized in that, The generation rate limit concentration The calculation formula is: ； in, and These represent the number of participating electrons in the half-electrode reaction and the stoichiometric coefficient of hydrogen, respectively. denoted as the volume current density of the electrode.

4. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 1, characterized in that, The domain of the dissolved hydrogen dynamic equilibrium module is set within the flow channel, diaphragm, and electrode, and its equilibrium equation is constructed based on the two-film mass transfer theory as follows: ； in, This indicates the output of hydrogen through electrolysis. This indicates the mass transfer of dissolved hydrogen to the gaseous state; This represents the transmembrane mass transfer of dissolved hydrogen.

5. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 1, characterized in that, The diffusion simulation module includes a concentration diffusion submodule, a convection diffusion submodule, and an electroosmotic diffusion submodule, which construct three parallel transport mechanisms of concentration diffusion, convection diffusion, and electroosmotic diffusion to jointly describe the migration and diffusion behavior of dissolved hydrogen in the electrolyzer.

6. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 5, characterized in that, The control equation for the concentration diffusion submodule is: ； in, This represents the mass flux of dissolved hydrogen transferred through concentration diffusion; It is the effective diffusion coefficient of dissolved hydrogen; The concentration gradient of dissolved hydrogen is represented by the following formula: ； in, Here is the reference diffusion coefficient of dissolved hydrogen in KOH solution at the reference temperature; The activation energy is the dissolved hydrogen in the KOH solution. This is the current temperature; This is a reference temperature.

7. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 5, characterized in that, The governing equations for the convection-diffusion submodule are as follows: ； in, This represents the mass flux of dissolved hydrogen transferred through convection and diffusion. The fluid velocity; This represents the concentration of dissolved hydrogen.

8. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolytic cell according to claim 5, characterized in that, The calculation equations for the electroosmotic diffusion submodule are as follows: ； in, This represents the mass flux of dissolved hydrogen transferred via electroosmosis diffusion; This represents the solubility of hydrogen. This is the electroosmotic drag coefficient.

9. The three-dimensional simulation method for dissolved hydrogen diffusion in an alkaline electrolyzer according to claim 5, characterized in that, The overall mass diffusion equation of the diffusion simulation module is: ； in, The source term of the mass diffusion equation is: .

10. A three-dimensional simulation system for the diffusion of dissolved hydrogen in an alkaline electrolyzer, used to execute the three-dimensional simulation method according to any one of claims 1-9, characterized in that, include: A three-dimensional geometric model module, comprising: an alkaline electrolytic cell unit consisting of bipolar plates, flow channels, electrodes, and a diaphragm; The dissolved hydrogen dynamic equilibrium module interacts with the three-dimensional geometric model module to simulate the mass transfer of dissolved hydrogen in the solution based on the three-dimensional geometric model, as well as the precipitation transfer calculation when dissolved hydrogen reaches supersaturation solubility. The diffusion simulation module interacts with the three-dimensional geometric model module and the dissolved hydrogen dynamic equilibrium module to calculate the concentration diffusion flux, convection diffusion flux and electroosmotic diffusion flux of dissolved hydrogen in the electrolyzer based on the three-dimensional geometric model, so as to simulate the diffusion and transfer process of dissolved hydrogen in the electrolyzer. The dynamic upper limit module for dissolved hydrogen concentration interacts with the three-dimensional geometric model module to dynamically correct the upper limit of dissolved hydrogen concentration based on the three-dimensional geometric model and according to the operating conditions. The dynamic upper limit module for dissolved hydrogen concentration includes a supersaturated solubility calculation unit. The supersaturated solubility calculation unit determines the theoretical solubility based on temperature, pressure and reduced solution concentration, and performs supersaturation correction on the theoretical solubility based on current density to construct the supersaturation limit concentration of dissolved hydrogen. The simulation construction module is connected to the dissolved hydrogen dynamic equilibrium module, the diffusion simulation module, and the dissolved hydrogen concentration dynamic upper limit module, respectively. It is used to associate the interaction information of each module and couple the supersaturation limit concentration determined by the dissolved hydrogen concentration dynamic upper limit module to the diffusion simulation module to construct a three-dimensional simulation model of dissolved hydrogen diffusion in the alkaline electrolyzer.

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