A method for predicting the microscopic leakage rate of the sealing interface of a hydrogen fuel cell
The microscopic contact sub-model of the sealing interface of hydrogen fuel cell is established through the G-W model, and numerical simulation and fluid mechanics calculations are carried out, which solves the accuracy and flexibility of the sealing performance prediction of hydrogen fuel cell, and achieves rapid and low-cost leakage rate monitoring and verification.
Patent Information
- Application Number
- CN202111504035.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-10
- Publication Date
- 2025-07-01
- Estimated Expiration
- 2041-12-10
AI Technical Summary
The prior art is difficult to accurately predict the sealing performance of hydrogen fuel cells, especially when external load changes, traditional leak detection equipment is poor in flexibility and low efficiency, and cannot monitor leakage points in real time, and it is difficult to fit the macroscopic and microscopic models.
A G-W surface morphology description model was used to establish a microscopic contact sub-model of the sealing interface of hydrogen fuel cell, perform sealing and compression numerical simulation, obtain the fluid leakage domain, and calculate the leakage amount through fluid mechanics simulation, and combine it with the finite element method to establish a bridge between the microscopic and the macroscopic.
It improves the accuracy and flexibility of leak rate prediction in the sealing interface of hydrogen fuel cell, simplifies the calculation process, reduces costs, and achieves rapid leakage rate monitoring and verification.
Smart Images
Figure CN114372388B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of hydrogen fuel cell seal detection, and in particular to a method for calculating and predicting the leakage rate of a hydrogen fuel cell that takes into account the random surface topography characteristics of the seal interface and the compression and gas flow principles of the seal at the microscale. Background Art
[0002] With the increasing severity of environmental pollution, energy security and other issues, it has become extremely urgent to find alternative energy sources for fossil fuels. Hydrogen energy is regarded as the "future energy" due to its high efficiency, cleanliness, economy, safety and other characteristics. Fuel cells are the main places for releasing hydrogen energy and are devices that convert internal energy into electrical energy. It is the fourth major power generation technology after hydraulic power generation, thermal power generation, and nuclear power generation, and is even considered the preferred clean and efficient power generation method in the 21st century.
[0003] Hydrogen fuel cells are widely used due to their high power density, high energy conversion efficiency, and relatively appropriate operating temperature. When a hydrogen fuel cell operates, it has extremely high requirements for the internal environment, including: the reaction gases should be maintained within an appropriate pressure range; the anode gas and the cathode gas should not leak internally or cross each other; there should be no impurities in the reaction space, etc.
[0004] Leakage affects the performance and safety of the entire hydrogen fuel cell stack and is an important indicator for judging whether the stack can operate safely and effectively. As an essential reaction gas for hydrogen fuel cells, hydrogen has characteristics such as a small molecular structure, light mass, and active properties. Once leakage occurs, hydrogen will quickly escape from the reaction space, the anode gas pressure of the hydrogen fuel cell will drop rapidly, and the stack efficiency will decrease until it fails. Moreover, hydrogen has strong flammability and explosiveness, and it is very likely to become the starting point of hazards such as combustion and explosion after leakage, directly endangering production safety.
[0005] A single hydrogen fuel cell has an output characteristic of "high current, low voltage". In order to make it meet the actual engineering use, generally 300 - 500 single cells are connected in series to form a stack. For the entire stack system, its series characteristics determine that if any component has a problem, the overall electrical efficiency of the stack will be greatly reduced or even the system will shut down due to failure. And there are hundreds or thousands of sealing surfaces in a hydrogen fuel cell stack. Leakage or internal cross - flow from any one of the sealing surfaces will seriously affect the overall electrical efficiency of the stack and even cause serious safety accidents such as fire and explosion.
[0006] As can be seen from the above, it is particularly important to predict the sealing performance of hydrogen fuel cells. However, in hydrogen fuel cells, affected by changing external loads (such as packaging force, temperature, vibration, etc.), the sealing state of the battery is very unstable, and parameters such as the shape and size of the gas leakage channels become difficult to predict, resulting in a significant reduction in the accuracy of the hydrogen fuel cell leakage rate model.
[0007] In industrial production, specialized leak detection equipment is used to measure the leakage rate of the entire hydrogen fuel cell stack. These leak detection devices are generally heavy and large in volume, and can only be fixed in one place. When the hydrogen fuel cell stack leaks during actual use, it is difficult to conduct leak detection work in real time and on site. Secondly, to obtain an accurate leakage rate, it is necessary to ensure that the fuel cell stack and the leak detection equipment operate normally for a long time simultaneously. The cycle is long and it is easily interfered by external factors. Moreover, when actually measuring the leakage rate of the hydrogen fuel cell, the leak detection equipment needs to work together with systems such as gas supply, humidification, cooling, dust prevention, and post-treatment. The entire set of systems has a cumbersome structure, great difficulty in correlation, high manufacturing cost, and poor maintainability. Especially when the working conditions of the hydrogen fuel cell stack are unstable and the external load changes greatly, the deficiencies of poor flexibility and low efficiency of this traditional leak detection system will become more obvious. And this method for detecting the leakage of the entire hydrogen fuel cell stack cannot specifically identify the leakage point, nor can it predict and control the leakage rate from the perspectives of practicality and safety.
[0008] In theoretical research, the current calculation models for the sealing leakage rate of hydrogen fuel cells mainly come from traditional mechanical seal leakage theories. Among them, several relatively common ones include the parallel plate gap flow theory, surface fractal theory, Persson rough surface penetration theory, Lattice Boltzmann Method (LBM), and Greenwood-Williamson (hereinafter referred to as G-W) random contact surface contact model. Through the theoretical prediction model of the hydrogen fuel cell leakage rate, the leakage rate under different working conditions and time points can be obtained. Compared with the actual measurement method in engineering, the theoretical calculation method has a short cycle, low cost, and is convenient for flexibly implementing boundary condition replacement. However, the predicted results of the above hydrogen fuel cell leakage calculation models for the leakage rate vary greatly and cannot be unified. Moreover, most of the leakage rate calculation models are derived by mathematical methods, and their connection with macroscopic methods is not close enough. Most importantly, there is a huge scale difference between the macroscopic leakage rate measurement method adopted in engineering and the microscopic calculation results of the theoretical model, making it difficult for the two to fit and mutually verify. Summary of the Invention
[0009] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a method for predicting the microscopic leakage rate of the sealing interface of a hydrogen fuel cell considering random surface topography.
[0010] The purpose of the present invention can be achieved through the following technical solutions:
[0011] A method for predicting the microscopic leakage rate of the sealing interface of a hydrogen fuel cell includes the following steps:
[0012] 1) Establish a microscopic contact pair model of the sealing interface of a hydrogen fuel cell with random characteristics through the G-W surface topography description model;
[0013] 2) Conduct a sealing compression numerical simulation experiment on the micro-contact pair model of the hydrogen fuel cell sealing interface to simulate the pre-tightening load and compression state of the seal during the assembly process of the hydrogen fuel cell, and thereby obtain the microscopic gap between the contact pairs after the sealing compression numerical simulation experiment, that is, the fluid leakage domain;
[0014] 3) Conduct a gas flow leakage simulation experiment on the fluid leakage domain to simulate the gas leakage of the hydrogen fuel cell sealing interface and obtain the leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface.
[0015] In the described step 1), observe the microscopic structure of the surface of the hydrogen fuel cell sealing contact components, obtain the morphological characteristics of the microscopic surface structure, quantify the morphological characteristics of the surface microstructure into specific parameters through the G-W surface topography description model, and establish a micro-contact pair of the hydrogen fuel cell sealing interface with a random surface rough structure according to the specific parameters.
[0016] The specific parameters include the radius r of the rough peak, the height h of the rough peak, the standard deviation σ of the normal distribution corresponding to the height h of the rough peak, and the rough peak density D.
[0017] In the described step 2), in the sealing compression numerical simulation experiment, make the load just contact the contact surface of the seal of the micro-contact pair of the hydrogen fuel cell sealing interface and the substrate of the bipolar plate seal surface to approximate the true compression and sealing state of the hydrogen fuel cell seal.
[0018] After the micro-contact pair of the hydrogen fuel cell sealing interface undergoes a sealing compression numerical simulation experiment, the microscopic gap between the contact pairs is the gas leakage channel of the hydrogen fuel cell sealing interface, that is, the fluid leakage domain.
[0019] In the described step 3), apply a fluid boundary load to the fluid leakage domain, conduct a finite element simulation of the microscopic gas flow in the fluid leakage domain, and obtain the leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface.
[0020] The leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface is represented by the mass Q of the gas flowing out of the leakage outlet, and there is:
[0021]
[0022] Among them, Q i is the gas leakage amount of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface, and n is the total number of units.
[0023] The gas leakage amount Q of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface i The calculation formula is:
[0024] Q i =ρ M·A i ·v i
[0025] where ρ M is the gas flow density, A i is the area of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface, and v i is the gas flow velocity of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface.
[0026] The area A i of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface has the following expression:
[0027] A i = ∫0 l [f(v i+1 ) - f(v i )]dv
[0028]
[0029] where f(v) is the curve expression of the gas flow velocity isoline on the gas outlet, and l and h are the width and height of the gas outlet respectively.
[0030] If the gas flow density in the gas outlet is uniform, the gas flow density ρ Mi of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface is M ρ = ρ
[0031] (i = 1, 2,..., n).
[0032] Compared with the prior art, the present invention has the following advantages:
[0033] 1. The present invention introduces the random distribution characteristics of the surface topography of the hydrogen fuel cell sealing interface, and the expression accuracy of the interface microscopic topography is high;
[0034] 2. The present invention does not specifically consider the quantitative influence of a certain parameter on the leakage channel size, shape and other indicators. Instead, it directly calculates the leakage rate, and the idea is more concise, and the leakage channel is intuitive and easy to observe;
[0035] 3. The present invention adopts the finite element mechanics method and fluid mechanics simulation with a short period, low cost, and clear boundary conditions; Description of the Drawings
[0036] Figure 1 It is a diagram of the hydrogen fuel cell sealing interface leakage rate prediction method involved in the present invention;
[0037] Figure 2 The contact pair model with a random surface roughness structure constructed according to the measurement results of the surface microstructure of the hydrogen fuel cell sealing interface in the embodiment;
[0038] Figure 3 The state and flow micro-gap after the sealing compression numerical simulation of the contact pair of the hydrogen fuel cell sealing interface in the embodiment;
[0039] Figure 4 The fluid leakage domain model of the hydrogen fuel cell sealing interface after the sealing compression simulation in the embodiment;
[0040] Figure 5 The fluid leakage simulation results of the hydrogen fuel cell sealing interface in the embodiment. Among them, Fig. (5a) is the pressure distribution diagram in the fluid leakage domain 4, and Fig. (5b) is the velocity distribution diagram.
[0041] Description of the marks in the figure
[0042] 1. Sealing surface of the seal, 2. Sealing surface of the bipolar plate, 3. Surface roughness peak, 4. Fluid leakage domain, 5. Gas inlet, 6. Region blocked by high roughness peaks, 7. Region not blocked by low roughness peaks, 8. Gas outlet. Detailed implementation manners
[0043] To make the above features and advantages of the present invention more obvious and understandable, prove the effectiveness of the method involved in the present invention, and briefly analyze the calculation process of the leakage amount of the hydrogen fuel cell sealing interface, specific embodiments are given below and are described in detail with the accompanying drawings. In this embodiment, the leakage of the sealing interface between the hydrogen fuel cell seal and the bipolar plate is selected for analysis.
[0044] Embodiment
[0045] The present invention relates to a method for predicting the microscopic leakage rate of the sealing interface of a hydrogen fuel cell considering random surface topography. Specifically, this method first establishes a microscopic contact pair model of the sealing interface of a hydrogen fuel cell with random characteristics through the G-W surface topography description model; conducts a numerical simulation experiment of seal compression on the microscopic contact pair model of the sealing interface to analogize the pre-tightening load and compression state of the seal during the assembly of the hydrogen fuel cell, and thereby obtains a CAD model of the gap between the sealing interfaces (i.e., microscopic contact pairs) during seal compression, which is called the fluid leakage domain; finally, conducts a gas flow leakage simulation experiment on the fluid leakage domain to simulate the gas leakage of the sealing interface of the hydrogen fuel cell, calculates the leakage amount of the microscopic sealing unit of the sealing interface of the hydrogen fuel cell. The leakage amount of the sealing interface of the hydrogen fuel cell obtained by the method of the present invention can not only be used as a direct verification of the theoretical calculation model of the leakage rate, but also obtain the macroscopic leakage rate through means such as superposition. The present invention also proposes a computer finite simulation experiment method for the leakage rate of the sealing interface of a hydrogen fuel cell, which makes up for the deficiencies of the macroscopic actual experiment method and the microscopic theoretical calculation method, builds a bridge between the two, provides a new basis and reference for the leakage of the sealing interface of a hydrogen fuel cell, and is an effective basis for predicting the leakage rate of a hydrogen fuel cell and monitoring the leakage point. The present invention fully considers the gas flow characteristics at the microscopic scale of the sealing interface of the hydrogen fuel cell and the surface rough peak structure of the sealing interface, refers to the actual links in the working process of the seal, and truly simulates the leakage situation of the sealed gas of the hydrogen fuel cell at the sealing interface, ensuring the feasibility and accuracy of the present invention.
[0046] The present invention includes the following steps:
[0047] 1) Observe the microscopic structure of the surface of the sealing contact components of the hydrogen fuel cell to obtain the microscopic surface structure topography characteristics;
[0048] Through the G-W surface topography description model, quantify the microscopic surface structure topography characteristics into specific parameters such as the radius r of the rough peak, the height h of the rough peak (the height difference between the center of the rough peak sphere and the base surface), the standard deviation σ of the normal distribution corresponding to the height h of the rough peak, and the density D of the rough peak;
[0049] 2) Establish a microscopic contact pair of the sealing interface of the hydrogen fuel cell with a random surface rough structure according to the specific parameters;
[0050] 3) Conduct a numerical experiment of seal compression for simulated assembly on the microscopic contact pair of the sealing interface of the hydrogen fuel cell;
[0051] 4) Observe the microscopic gap between the contact pairs after the numerical simulation experiment of seal compression;
[0052] The microscopic gap between the contact pairs is the gas leakage channel of the sealing interface of the hydrogen fuel cell, which is called the fluid leakage domain in the present invention;
[0053] 5) Apply a fluid boundary load to the fluid leakage domain and analyze the leakage amount of the microscopic sealing unit at the hydrogen fuel cell sealing interface;
[0054] The leakage amount of the microscopic sealing unit at the hydrogen fuel cell sealing interface is represented by the mass Q of the gas at the leakage outlet, and its unit is kilograms per second;
[0055] The mass Q of the gas at the leakage outlet is represented by the mass Q of the gas flow through different units i i ;
[0056] Different units i are obtained by differentiating the gas velocity contour lines on the leakage outlet surface. The gas leakage mass Q on unit i i is calculated from the area A of this unit i , the gas flow density ρ within the unit surface Mi and the gas velocity v. i It is calculated.
[0057] Combined with the appendix Figure 2 The process of establishing the contact pair of the hydrogen fuel cell sealing interface with a random rough peak structure using the G-W surface topography description model is described in detail as follows:
[0058] After observing the microscopic topography of the hydrogen fuel cell seal and the bipolar plate surface, it is found that the rough peak characteristics of the seal and the bipolar plate surface have the following relationship:
[0059]
[0060] In the formula, the subscripts gk and BPP represent the seal and the bipolar plate in the contact pair of the hydrogen fuel cell sealing interface respectively.
[0061] On the premise of not affecting the rationality of the method of the present invention, following the principle of simplifying the model and reducing the calculation amount, according to the above microscopic rough peak characteristics of the seal and the bipolar plate, this embodiment sets a contact pair model of a single rough peak seal surface 1 and a multi-rough peak bipolar plate seal surface 2.
[0062] There is only a single rough peak on the surface of the seal surface 1. Therefore, the height difference of the rough peaks is not considered, and its height is selected as the standard value. In order to improve the calculation efficiency and ensure the integrity and effective sealing of the single rough peak on the seal surface 1 after seal compression, this embodiment selects the rough peaks on the surface of the bipolar plate seal surface 2 to be distributed in a 4×4 manner. The height h of these rough peaks satisfies a normal distribution of σ = 0.848 (obtained by measurement), and a 4×4 numerical grid satisfying the following normal characteristics is generated, h i is the height of each rough peak:
[0063] h ~ N(0, σ 2 ) (i = 1, 2,..., 16)
[0064] According to h i (i = 1, 2, ..., 16) and r gk Model the contact pair of the hydrogen fuel cell sealing interface with the parameter pair, and the results are specifically as Figure 2 shown. The label 3 is the surface rough peaks with random characteristics and their distribution.
[0065] Combined with Figure 3 、 Figure 4 Details of the sealing compression numerical simulation experiment and the characteristics of the fluid leakage domain for battery stack assembly are described in detail as follows:
[0066] Conduct a sealing compression numerical simulation experiment on the contact pair model of the hydrogen fuel cell sealing interface. The load just makes the contact surface 1 of the seal and the substrate of the bipolar plate sealing surface 2 contact to approximate the real pressure-sealed state of the hydrogen fuel cell seal. The results are as Figure 3 shown. It can be clearly seen that after the sealing compression experiment on the seal, there is still a gap between the sealing surface 1 of the seal and the bipolar plate seal 2 at the micro scale. This gap is the fluid leakage domain 4 of the hydrogen fuel cell sealing interface.
[0067] For the convenience of the next computer finite element simulation of fluid leakage, the above fluid leakage domain 4 needs to be extracted as an entity, as Figure 4 shown. It consists of the following parts: gas inlet 5, gas outlet 8, the region 6 blocked by high rough peaks, the region 7 not blocked by short rough peaks, and the other surfaces are the boundaries of the gas flow region. The entity enclosed by each surface is the fluid leakage domain 4.
[0068] Combined with Figure 5 Details of the finite element simulation of the gas micro-flow and the calculation of the leakage amount in the fluid leakage domain of the hydrogen fuel cell sealing interface are described in detail as follows:
[0069] Figure 5 It is a diagram of the gas flow leakage result in the fluid leakage domain of the hydrogen fuel cell sealing interface. Figure (5a) is the pressure distribution diagram in the fluid leakage domain 4. It can be seen that the pressure decreases in a gradient from the gas inlet 5 to the gas outlet 8 direction, and the pressure at the gas outlet 8 is the lowest; high-pressure areas are formed around the rough peaks, and the leaked gas accumulates in these areas, reducing further leakage. Figure (5b) is the velocity distribution diagram. It can be seen that the overall gas velocity in the fluid leakage domain 4 is slow, and only high-velocity vortices are formed in some rotating regions. From this, it can be judged that under the experimental conditions, the gas velocity at the gas outlet 8 is low, the pressure is small, and the gas flow rate at the gas outlet 8 is small, and the hydrogen fuel cell seal has a good sealing effect.
[0070] The method involved in the present invention can directly use the gas throughput at the gas outlet 8 as the leakage amount of the micro unit of the hydrogen fuel cell sealing interface, which is simple, straightforward, and convenient for analysis and prediction. This embodiment will also be described in detail. The gas flow density ρM It indicates the degree of sparsity of the gas distribution in a cross-section, which is related to the gas pressure generated by the gas in this cross-section and can be obtained by converting the gas pressure in the cross-section; the gas flow velocity v represents the amount of gas molecules passing through the cross-section per unit time.
[0071] Combined with this embodiment, it illustrates the prediction model for the leakage amount Q of the sealing interface of the hydrogen fuel cell in the method involved in the present invention. As can be seen above, the mass Q of the gas flowing out from the gas outlet 8 represents the microscopic leakage amount of the sealing unit of the hydrogen fuel cell sealing cross-section, and Q is composed of the outflow amounts Q i superimposed, that is:
[0072]
[0073] where the gas flow velocity v of the i-th unit i can be directly obtained from the gas velocity data of the gas outlet 8.
[0074] According to the definition, the area A of the i-th unit i is:
[0075]
[0076] f(v) is the curve expression of the gas flow velocity contour line on the gas outlet 8, and it has the following characteristics:
[0077]
[0078] where l and h are the width and height of the gas outlet 8 respectively.
[0079] Finally, in the method involved in the present invention, it can be considered that the gas flow density in the gas outlet 8 is uniform, so the gas flow density ρ of the i-th unit Mi is:
[0080] ρ Mi =ρ M (i = 1, 2,..., n)
[0081] Finally, the gas leakage amount Q on the i-th unit i is:
[0082] Q i =ρ M ·A i ·v i (3)
[0083] According to the finite element simulation of the microscopic flow of the fluid leakage domain of the hydrogen fuel cell sealing interface and formulas (1) to (3), the microscopic leakage amount Q of the sealing unit of the hydrogen fuel cell sealing interface in this embodiment can be calculated as:
[0084] Q = 5.73×10 -20 kg / s
[0085] In summary, the present invention uses a random surface description model to model the surface of the hydrogen fuel cell sealing contact interface, and proposes a computer finite element calculation method for the leakage rate of the hydrogen fuel cell sealing interface at the microscale. On the one hand, the present invention avoids calculation deviations that may be caused by scale effects. On the other hand, the present invention uses the random surface topography theory to describe the micro-rough peaks of the hydrogen fuel cell contact interface, making the experimental model more general and universal. By directly calculating the leakage rate through the finite element experimental method, it can effectively serve as a bridge between macroscopic leak detection and microscale calculation and a fast and efficient verification method for different leakage rate calculation models.
[0086] In addition, the present invention takes the micro-sealing unit of the hydrogen fuel cell sealing interface as the experimental unit, and proposes a finite element prediction method for the leakage rate of the hydrogen fuel cell sealing interface. Through the present invention, not only can the leakage rate of the hydrogen fuel cell sealing interface be simply, directly and quickly obtained, but also when the external load and working environment change, it has the ability to quickly adjust the experimental constraint conditions to adapt to different working conditions. Finally, the finite element calculation method for the leakage rate of the hydrogen fuel cell sealing interface involved in the present invention provides a basis for further calculating the leakage rate of the hydrogen fuel cell in a wide temperature range and the entire time domain, and provides a basis for improving and perfecting the hydrogen fuel cell leakage rate prediction model and enhancing the sealing reliability.
Claims
1. A method for predicting the microscopic leakage rate of the sealing interface of a hydrogen fuel cell, characterized in that, It includes the following steps: 1) Establish a microscopic contact pair model of the hydrogen fuel cell sealing interface with random features through the G-W surface topography description model; 2) Conduct a sealing compression numerical simulation experiment on the microscopic contact pair model of the hydrogen fuel cell sealing interface to simulate the pre-tightening load and compression state of the seal during the assembly process of the hydrogen fuel cell, and thereby obtain the microscopic gap between the contact pairs after the sealing compression numerical simulation experiment, that is, the fluid leakage domain; 3) Conduct a gas flow leakage simulation experiment on the fluid leakage domain to simulate the gas leakage of the hydrogen fuel cell sealing interface and obtain the leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface; In step 1), observe the microscopic structure of the surface of the hydrogen fuel cell sealing contact components to obtain the microscopic surface structure topography characteristics, and quantify the surface microscopic structure topography characteristics into specific parameters through the G-W surface topography description model, and establish a microscopic contact pair of the hydrogen fuel cell sealing interface with a random surface rough structure according to the specific parameters; The specific parameters include the rough peak radius r, the rough peak height h, the standard deviation σ of the normal distribution corresponding to the rough peak height h, and the rough peak density D; In step 3), apply a fluid boundary load to the fluid leakage domain and conduct a finite element simulation of the microscopic gas flow in the fluid leakage domain to obtain the leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface; The leakage amount of the microscopic sealing unit of the hydrogen fuel cell sealing interface is represented by the mass Q of the gas flowing out of the leakage outlet, and there is: Among them, Q i is the gas leakage of the i-th micro-sealing unit of the hydrogen fuel cell sealing interface, and n is the total number of units; The gas leakage Q of the i-th micro-sealing unit at the hydrogen fuel cell sealing interface i is calculated by the formula: Q i = ρ M · A i · v i Among them, ρ M is the gas flow density, A i is the area of the i-th micro-sealing unit of the hydrogen fuel cell sealing interface, and v i is the gas flow velocity of the i-th micro-sealing unit of the hydrogen fuel cell sealing interface; The area A of the i-th microscopic sealing unit of the hydrogen fuel cell sealing interface i has the following expression: where f(v) is the curve expression of the gas velocity contour line on the gas outlet, and l and h are the width and height of the gas outlet respectively.
2. The method for predicting the microscopic leakage rate of a hydrogen fuel cell sealing interface according to claim 1, wherein In step 2), in the sealing compression numerical simulation experiment, make the load just contact the contact surface of the seal of the microscopic contact pair of the hydrogen fuel cell sealing interface and the substrate of the bipolar plate sealing surface to approximate the actual compression sealing state of the hydrogen fuel cell seal; 3. A method for predicting the microscopic leakage rate of a hydrogen fuel cell sealing interface according to claim 2, characterized in that, After the microscopic contact pair of the hydrogen fuel cell sealing interface undergoes a sealing compression numerical simulation experiment, the microscopic gap between the contact pairs is the gas leakage channel of the hydrogen fuel cell sealing interface, that is, the fluid leakage domain.
4. A method for predicting the microscopic leakage rate of a hydrogen fuel cell sealing interface according to claim 1, characterized in that If the gas flow density in the described gas outlet is uniform, then the gas flow density ρ of the i-th micro-sealing unit of the hydrogen fuel cell sealing interface Mi = ρ M (i = 1, 2, …, n).