CN113761767B - Method for designing section of sealing element of hydrogen fuel cell by accounting for alternating temperature influence - Google Patents
Method for designing section of sealing element of hydrogen fuel cell by accounting for alternating temperature influence Download PDFInfo
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- 238000007789 sealing Methods 0.000 title claims abstract description 142
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 94
- 239000001257 hydrogen Substances 0.000 title claims abstract description 93
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 93
- 239000000446 fuel Substances 0.000 title claims abstract description 92
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- 238000004806 packaging method and process Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
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- 239000003566 sealing material Substances 0.000 description 1
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Abstract
The invention relates to a method for designing a section of a sealing element of a hydrogen fuel cell, which takes into account alternating temperature influence, comprising the following steps of: 1) Acquiring a curve of the mechanical property of the section of the hydrogen fuel cell sealing element under different temperature conditions along with the time change; 2) Obtaining a design principle of the section of the sealing element of the hydrogen fuel cell according to a curve of the mechanical property changing along with time; 3) And (3) carrying out the optimized design of the section of the sealing element of the hydrogen fuel cell by combining with the design principle, and verifying through finite element simulation to ensure that the sealing element meets the design requirement. Compared with the prior art, the invention has the advantages of being close to actual working conditions, strictly designed and the like.
Description
Technical Field
The invention relates to the field of hydrogen fuel cell seal design, in particular to a method for designing a section of a hydrogen fuel cell seal part by accounting for alternating temperature influence.
Background
Along with the increasing serious problems of environmental pollution, energy safety and the like, it is urgent to find alternative energy sources of fossil fuels, and hydrogen energy is regarded as 'future energy source' by people due to the characteristics of high efficiency, cleanness, economy, safety and the like. The fuel cell is a main place for releasing hydrogen energy and is a generating device for converting internal energy into electric energy; the method is a fourth power generation technology after hydroelectric power generation, thermal energy power generation and atomic energy power generation, and is more considered as a clean and efficient power generation mode preferred in the 21 st century.
Hydrogen fuel cells are widely used with higher power density and energy conversion efficiency, and more suitable operating temperatures. The hydrogen fuel cell has extremely high requirements on the internal environment during operation: the reaction gas should be maintained within a suitable pressure range; the anode gas and the cathode gas should not leak and cross each other; impurities and the like cannot exist in the reaction space. In short, the sealing member in the hydrogen fuel cell plays an important role of 'outer leakage prevention and inner blowby prevention'.
At present, the conventional mechanical seal theory is generally adopted as a reference when the design of the sealing element of the hydrogen fuel cell is carried out, but the theory is difficult to be well applied to the sealing design of the hydrogen fuel cell; this is because the O-ring seal employed in the conventional mechanical seal has the characteristics of simple cross-sectional shape, single ring shape, small Zhou Changjiao, etc., while the hydrogen fuel cell is sealed using a large-circumference seal member and its cross-sectional shape is complex.
In addition to geometrically differing from conventional seals, hydrogen fuel cell seals are also more complex to subject to external effects: largely alternating operating temperatures; the simultaneous effects of encapsulation force, gas side force and friction force; chemical reaction with a reaction gas (hydrogen gas), and the like. These loads and constraints directly determine the performance and service life of the hydrogen fuel cell seal. Among the above factors, the temperature has the most pronounced effect on the sealing performance of a hydrogen fuel cell: the temperature directly changes the mechanical property, the dimensional parameter and the like of the sealing element, and then changes the real compression rate of the sealing element in the working state, thereby determining the real contact stress and the internal stress during sealing.
There are two main modes of temperature effects on hydrogen fuel cell seals, on the one hand, the operating temperature at which the seal is located can directly affect the modulus of elasticity of the seal material. In a low temperature environment, the sealing element material is 'hardened', and the elastic modulus is increased; in high temperature environments, the seal material "softens" and the modulus of elasticity decreases. On the other hand, after the mechanical properties of the sealing element materials are changed, the number and the width of the gas leakage channels are different from those of the state at normal temperature, and the real leakage rate of the sealing element is difficult to predict; at the same time, the friction force, contact state and the like of the sealing element and other parts can be changed, and the actual service life of the sealing element can also show nonlinear change.
It can be seen above that the effect of temperature on hydrogen fuel cell seal performance is not negligible, and will be more pronounced when the temperature alternates. When the sealing element is in an alternating temperature environment, the elastic deformation of the sealing element material gradually changes to the non-rebounding plastic deformation, the actual compression ratio of the sealing element continuously changes, the contact stress and the internal stress of the sealing element periodically change, and finally the tightness and the service life of the hydrogen fuel cell sealing element at the alternating temperature are difficult to analyze. The current seal design of the hydrogen fuel cell only considers the influence of a single temperature (constant high temperature or constant low temperature) on the sealing performance, and the irreversible change generated by the seal performance under alternating temperature is not fully considered, so that the true sealing performance and the actual service life of the hydrogen fuel cell are greatly different from the theoretical value.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method for designing the section of the sealing element of the hydrogen fuel cell, which takes into account the influence of alternating temperature on the mechanical property of the sealing element.
The aim of the invention can be achieved by the following technical scheme:
a method of designing a hydrogen fuel cell seal cross-section that accounts for alternating temperature effects, comprising the steps of:
1) Acquiring a curve of the mechanical property of the section of the hydrogen fuel cell sealing element under different temperature conditions along with the time change;
2) Obtaining a design principle of the section of the sealing element of the hydrogen fuel cell according to a curve of the mechanical property changing along with time;
3) And (3) carrying out the optimized design of the section of the sealing element of the hydrogen fuel cell by combining with the design principle, and verifying through finite element simulation to ensure that the sealing element meets the design requirement.
The step 1) specifically comprises the following steps:
11 Acquiring the temperature characteristics of the hydrogen fuel cell during operation, including the lowest cold start temperature and the highest operating temperature;
12 Setting a typical seal temperature condition according to the temperature characteristics of the hydrogen fuel cell during operation;
13 Obtaining the mechanical parameters of the hydrogen fuel cell sealing element under each working condition through finite element simulation.
In step 12), typical seal temperature conditions include constant temperature conditions and alternating temperature conditions.
The alternating temperature working condition is a three-cycle alternating temperature working condition serving as a limiting working condition, and specifically comprises the following steps:
the 24 hours were equally divided into three cycles, one for every 8 hours, each temperature cycle comprising 4 phases, then there were:
(1) The first 2 hours are the working temperature rising stage of the hydrogen fuel cell, the first hour rises from-40 ℃ to 20 ℃ and the second hour rises from 20 ℃ to 100 ℃;
(2) The 3 rd to 5 th hours are temperature keeping stages, and the temperature is constant at 100 ℃;
(3) The 6 th hour is a natural temperature reduction stage;
(4) The last two hours are the low temperature rest phase, and the temperature is kept at-40 ℃.
The mechanical properties are specifically as follows:
after the hydrogen fuel cell seal is subjected to an initial compression ratio, the maximum contact stress and the average internal stress generated under different temperature conditions,
according to the Hertz contact theory and a rubber material life model, the maximum contact stress is used as the mechanical expression of the sealing performance, and the average internal stress is used as the judging basis of the life of the sealing element.
In the step 2), the design principle of the section is specifically as follows:
the sealing performance of the hydrogen fuel cell seal is positively correlated with the maximum contact stress, the service life of the hydrogen fuel cell seal is negatively correlated with the average internal stress, and the sealing performance of the seal when in compression contact is enhanced by increasing the maximum contact stress and the overall service life of the seal is improved by reducing the average internal stress when in cross-section design.
The step 3) specifically comprises the following steps:
31 Acquiring an initial hydrogen fuel cell seal cross-sectional design;
32 Modifying and optimizing the initial scheme according to the optimization modification mode corresponding to the design principle;
33 Performing finite element simulation experiments on the optimized design scheme to obtain mechanical characteristics under the working condition of alternating temperature, if the design requirement is met, completing the design, otherwise, returning to the step 32).
In the step 32), the optimizing and modifying manner includes:
slowing the edge curvature to reduce stress concentration, taking an arch structure to enhance stability and improve overall internal stress distribution, and coordinating different contact area height differences to achieve multi-segment sealing contact under the same compression.
Each optimization modification mode specifically comprises the following means:
slowing down edge curvature: the curvature of the vertex angle of the cross section is reduced, so that the stress concentration phenomenon at the transition position of the vertex angle and the upper plane is improved, and meanwhile, the good contact state of the original model can be maintained;
altering the base angle shape: the bottom corner is changed into a round corner from the original right angle, so that the material tearing phenomenon caused by stress concentration is effectively relieved;
removing the inner space: the whole sealing piece adopts an arch structure, on one hand, the structure can well improve the average internal stress distribution of the whole sealing piece, so that the internal stress at each position tends to be average, and on the other hand, the support at the two ends of the arch structure can improve the gesture stability of the sealing piece when being pressed;
coordinating different zone height differences: the average internal stress of the sealing element is improved and the stress concentration phenomenon is avoided through the three means, but the contact stress is reduced, and then the sealing performance is influenced, so that the sealing performance of the sealing element is not inhibited by two mechanical indexes, the heights of different areas are adjusted, the real compression rate between the areas is changed, and the average internal stress of a specific area can be effectively reduced on the premise that the contact stress is basically unchanged.
Compared with the prior art, the invention has the following advantages:
1. the maximum contact stress and average internal stress values are convenient to acquire, and the comparison among the mechanical parameters is direct, so that the influence of alternating temperature on the performance of the hydrogen fuel cell sealing element can be conveniently and intuitively discovered;
2. the three-cycle alternating temperature working condition of-40 ℃ to 100 ℃ is set, and the severe working condition of the temperature change range of 140 ℃ can more strictly verify the resistance of the hydrogen fuel cell sealing element to the alternating temperature, and is also more close to the real working condition;
3. the invention provides a design method of a sealing element section under an alternating temperature working condition, which has theoretical reference significance for improving the sealing property and the service life of the sealing element in an alternating temperature environment.
Drawings
Fig. 1 is a flow chart for verifying the effect of crossover temperature on hydrogen fuel cell seal performance in accordance with the present invention.
Fig. 2 is a model of the dimensions of a control hydrogen fuel cell seal employed in an embodiment of the present invention.
Fig. 3 is a model of experimental hydrogen fuel cell seal dimensions used in an example of the invention.
FIG. 4 shows temperature parameters set in an embodiment of the present invention.
Fig. 5 is a comparison of mechanical parameters of interfaces of the sealing members of the control group under constant temperature and alternating temperature conditions in example 1, wherein fig. 5a is a case of stress at each temperature, fig. 5b is a case of variation of maximum contact stress with temperature cycle, and fig. 5c is a case of variation of internal stress with temperature cycle.
Fig. 6 is a comparison of mechanical parameters of cross sections of the sealing members of the control group and the experimental group at alternating temperatures in example 2, wherein fig. 6a is a change of maximum contact stress of the sealing members of the control group and the experimental group at alternating temperatures, and fig. 6b is a change of internal stress of the sealing members of the control group and the experimental group at alternating temperatures.
Detailed Description
In order to make the above features and advantages of the present invention more comprehensible, demonstrate the effectiveness of the present invention related to a method and briefly analyze the effect of alternating temperatures on hydrogen fuel cell seals, specific examples are described below in connection with the accompanying drawings.
Because hydrogen fuel cells have the output characteristics of large current and small voltage, 300-500 cells are generally connected in series to form a galvanic pile in order to enable the hydrogen fuel cells to meet the practical engineering use. For the whole stack system, the serial characteristic determines that any part is problematic, and the electric efficiency of the whole stack can be greatly reduced or even stopped in a failure mode. Hundreds of thousands of sealing elements exist in a hydrogen fuel cell stack, and the sealing elements are extremely easy to have the problems of unstable contact state, rapid rise of internal stress, even cracking and the like at alternating temperature, and the unstable property of the sealing elements at the alternating temperature has become an important factor for limiting the whole stack efficiency and service life of the hydrogen fuel cell. The anode or cathode seal of each hydrogen fuel cell unit may be referred to as a "one-layer" seal. Because of the characteristics of different heating of the anode and the cathode of the hydrogen fuel cell, different heating of different areas, different sealing force and gas pressure of different areas, and the like, the actual compression ratios of the same layer of sealing element at different section positions are also different, so that the sealing performance and degradation curves of the same layer of sealing element are also different. In order to fully ascertain the influence of alternating temperature on the sealing of the hydrogen fuel cell layers and the sealing of the stack, the mechanical change characteristics of the single sealing section under the alternating temperature are explored from the single sealing section, and the superposition of a plurality of sealing sections can form a sealing element, so that the thought and the basis are provided for the whole stack sealing design.
The invention provides a method for designing a section of a sealing element of a hydrogen fuel cell, which takes into account the influence of alternating temperature, comprising the following steps:
firstly, analyzing the influence of alternating temperature on the tightness and service life of a sealing element by comparing the mechanical properties of the sealing element under different temperature conditions of the section (control group) of the traditional sealing element;
then, a sealing member section design method with good resistance to alternating temperature is provided, and a finite element simulation experiment verification is carried out on a novel section (experimental group).
The specific explanation of each step is as follows:
1) Temperature characteristics of the hydrogen fuel cell during operation are obtained: the minimum cold start temperature is as low as-40 ℃, and the maximum working temperature is as high as 90 ℃;
2) Setting typical sealing member temperature working conditions including typical constant temperature working conditions and alternating temperature working conditions according to the temperature characteristics of the hydrogen fuel cell during operation;
3) Obtaining mechanical parameters of the hydrogen fuel cell sealing member under the working conditions of high temperature and alternating temperature by a finite element simulation experiment method, wherein the mechanical parameters specifically refer to maximum contact stress and average internal stress generated in different temperature environments after the hydrogen fuel cell sealing member is subjected to initial compression rate;
in the analysis of the alternating temperature working condition, the numerical value of the mechanical parameter of the sealing element changes with time after the initial compression rate is influenced by the alternating temperature, so that a curve of the maximum contact stress and the average internal stress changing with time is adopted as an analysis basis;
according to the prior Hertz contact theory and a rubber material life model, the maximum contact stress is a mechanical expression of sealing performance of the sealing element, and the average internal stress is a judging basis of the life of the sealing element.
According to the theory of contact mechanics and the theory of ageing of rubber materials, the sealing performance of the hydrogen fuel cell sealing element is considered to be in positive correlation with the maximum contact stress, and the service life of the hydrogen fuel cell sealing element is considered to be in negative correlation with the average internal stress.
4) When the section of the sealing element of the hydrogen fuel cell is designed, a region with larger contact stress value is reserved for enhancing the tightness of the sealing element when the sealing element is in pressed contact; deleting the region with larger internal stress and optimizing the stress concentration phenomenon, reducing the average internal stress of the sealing element, improving the overall service life of the sealing element, and specifically modifying and designing the model of the control group as follows:
(1) Reducing curvature of the top angle of the model of the control group and changing shape of the bottom angle of the model, so as to directly improve stress concentration phenomenon at the joint of the top angle and the top surface and at the bottom angle, and simultaneously ensure that the contact state is basically unchanged;
(2) The height of the top angles is reduced, the actual compression rate of the sealing element is reduced when the height of the two top angles is reduced under the condition that the overall compression rate of the sealing element is unchanged, the average internal stress is reduced along with the reduction, and the contact stress at the top angles after improvement is basically unchanged through calculation, so that the original tightness is maintained;
(3) The internal space of the control group model is removed, the experimental group model with the arch structure can ensure the installation stability, balance the overall average internal stress of the sealing element, and finally provide space for the shrinkage change of the sealing section under the influence of temperature, and maintain the stability of the mechanical property of the sealing element.
The present example is described with reference to fig. 2 as a comparative hydrogen fuel cell sealing structure, which is specifically as follows:
the hydrogen fuel cell sealing element is simultaneously contacted with the MEA frame and the BPP sealing groove, and generates compression deformation under the action of packaging force, thereby achieving the sealing effect. As shown in fig. 2, the control group model adopted in the embodiment of the invention is a trapezoid seal groove, and specific parameters are shown in fig. 2. The control group section adopts a wide D shape, the sealing element of the type is most widely applied to hydrogen fuel cells, has better stability, and the detailed size parameters are shown in figure 2. The initial height of the sealing element is 0.57mm, the compressed height is 0.405mm, the initial compression ratio is 28.95%, the setting not only meets the gap requirement between the MEA and the BPP after the compressed sealing of the hydrogen fuel cell, but also ensures that the sealing element is in the proper compression ratio range of the rubber material.
The alternating temperature conditions set in the present invention will be described with reference to fig. 4, which is as follows:
the invention sets three-cycle alternating temperature conditions, and is specifically stated with reference to fig. 4. Each temperature cycle involved 8 hours and was divided into 4 phases:
(1) The first 2 hours are the working temperature rising stage of the hydrogen fuel cell, the first hour rises from-40 ℃ to 20 ℃ and the second hour rises from 20 ℃ to 100 ℃;
(2) The 3 rd to 5 th hours are temperature keeping stages, and the temperature is constant at 100 ℃;
(3) The 6 th hour is a natural temperature drop stage, and is represented by a dotted line in fig. 4;
(4) The last two hours are the low temperature rest phase, and the temperature is kept at-40 ℃. The three alternating temperature cycles are completed for 24 hours to form a complete alternating temperature working condition.
Example 1
The mechanical parameters of the hydrogen fuel cell seal under constant temperature and alternating temperature conditions of the control group are analyzed in combination with fig. 5, and are specifically described as follows:
in this example, a conventional wide D-type hydrogen fuel cell seal cross section was selected as the control group.
Three typical temperatures of the hydrogen fuel cell sealing element working are respectively low temperature (-40 ℃), normal temperature (20 ℃) and high temperature (100 ℃), and when the temperature is from low to high, the maximum contact stress is gradually reduced and is sequentially 4.67MPa, 3.21MPa and 1.58MPa through a computer finite element simulation experiment; the average internal stress of the sealing element and the variation trend of the maximum contact stress are the same, and the average internal stress of the sealing element and the variation trend of the maximum contact stress are 4.32MPa, 3.08MPa and 1.62MPa in sequence.
From the results presented in fig. 5a and the basis for maximum contact stress response hydrogen fuel cell seal sealing, average internal stress response seal life, it can be derived that: the hydrogen fuel cell seal has optimal sealability at-40 ℃ and optimal service life at 100 ℃. It is clear that these conclusions do not fully match the true hydrogen fuel cell seal tightness and life distribution, since the mechanical index is complex non-linear when mapped to specific properties, and the present invention will not elaborate on the errors that occur, but focus on verifying the effect of alternating temperatures on the mechanical index of the hydrogen fuel cell seal.
By observing fig. 5b and 5c, it can be seen that after three temperature cycles, the maximum contact stress gradient of the hydrogen fuel cell seal decreases and the average internal stress gradient increases. Even though the mechanical parameters of the seal may be restored to the original level during the cold rest phase, it is well documented that the mechanical properties of the seal become increasingly lower than the original level with alternating temperature cycles, which is a significant difference from the stable mechanical properties exhibited by the seal at constant temperature. At around 1 hour, the graph of fig. 5 produced sharp corners due to the large fluctuations that occur when the temperature load first acted on the seal in a computer finite element simulation experiment.
As can be seen from the observation of the values of the mechanical parameters at constant temperature and alternating temperature in FIG. 5, the alternating temperature not only can cause the mechanical index of the sealing element to change in gradient, but also can change the amplitude of the mechanical index, the maximum contact stress of the sealing element of the hydrogen fuel cell in the alternating temperature environment is approximately equal to the value at normal temperature, the maximum contact stress gradually becomes smaller along with the influence of the alternating temperature on the property of the sealing material, and the sealing gradient of the sealing element is reduced under multiple cycles, so that the sealing state is more similar to the sealing state at high temperature. The same idea is used to obtain the variation characteristics of the internal stress of the hydrogen fuel cell sealing member at alternating temperatures.
Example 2
The mechanical parameters of the hydrogen fuel cell seal under alternating temperature conditions of the control group and the experimental group are analyzed in combination with fig. 6, and are specifically described as follows:
in this embodiment, the design of the hydrogen fuel cell seal against the alternating temperature influence cross section is completed. According to the method and the thought related by the invention, the average internal stress of the section of the novel sealing element is reduced, the contact stress distribution and the contact state of the section during sealing are improved, and the gradient degradation phenomenon of the mechanical property of the sealing element along with the temperature circulation is avoided, wherein a specific model is shown in figure 3.
By combining the graph (6 a), the section of the hydrogen fuel cell sealing element obtained by the method is shown that the maximum contact stress at high temperature is smaller than the value at low temperature, but the change period and the amplitude of the sealing element are more accurate under the influence of alternating temperature, and the sealing element does not show gradient change. In connection with the graph (6 b), it can likewise be seen that the variation of the average internal stress also becomes "uniform, trace-free", and the phenomenon of gradient rise is also avoided.
The method provides stable and effective guarantee for analyzing the mechanical properties of the section of the sealing element of the hydrogen fuel cell under the working condition of alternating temperature, so that the long-time quantitative analysis of the performance of the sealing element is possible. The above examples verify and document the method of the present invention, which are set forth and subdivided in the spirit of the invention and are not limiting of the invention. The protection scope of the present invention shall be subject to the claims.
In summary, the invention improves the tightness of the hydrogen fuel cell seal and the accuracy of the theoretical analysis of the service life under the alternating temperature environment, can provide basis for the seal design with lower leakage and long service life of the hydrogen fuel cell, fully considers the actual alternating temperature working condition of the hydrogen fuel cell, selects the typical constant temperature working condition and the working condition with the design close to the actual alternating temperature, and ensures the accuracy.
Claims (2)
1. A method of designing a hydrogen fuel cell seal cross-section to account for alternating temperature effects, comprising the steps of:
1) Acquiring a curve of the mechanical property of the section of the hydrogen fuel cell sealing element under different temperature conditions along with the time change;
2) Obtaining a design principle of the section of the sealing element of the hydrogen fuel cell according to a curve of the mechanical property changing along with time;
3) The design principle is combined to carry out the optimization design of the section of the sealing element of the hydrogen fuel cell, and verification is carried out through finite element simulation, so that the sealing element meets the design requirement;
the step 1) specifically comprises the following steps:
11 Acquiring the temperature characteristics of the hydrogen fuel cell during operation, including the lowest cold start temperature and the highest operating temperature;
12 Setting a typical seal temperature condition according to the temperature characteristics of the hydrogen fuel cell during operation;
13 Obtaining mechanical parameters of the hydrogen fuel cell sealing element under each working condition through finite element simulation;
in the step 12), typical sealing member temperature working conditions comprise constant temperature working conditions and alternating temperature working conditions;
the alternating temperature working condition is a three-cycle alternating temperature working condition serving as a limiting working condition, and specifically comprises the following steps:
the 24 hours were equally divided into three cycles, one for every 8 hours, each temperature cycle comprising 4 phases, then there were:
(1) The first 2 hours are the working temperature rising stage of the hydrogen fuel cell, the first hour rises from-40 ℃ to 20 ℃ and the second hour rises from 20 ℃ to 100 ℃;
(2) The 3 rd to 5 th hours are temperature keeping stages, and the temperature is constant at 100 ℃;
(3) The 6 th hour is a natural temperature reduction stage;
(4) The last two hours are low-temperature resting stages, and the temperature is kept at-40 ℃;
the mechanical properties are specifically as follows:
after the hydrogen fuel cell seal is subjected to an initial compression ratio, the maximum contact stress and the average internal stress generated under different temperature conditions,
according to the Hertz contact theory and a rubber material life model, the maximum contact stress is used as a mechanical expression of sealing performance, and the average internal stress is used as a judging basis of the life of the sealing element;
in the step 2), the design principle of the section is specifically as follows:
the sealing performance of the hydrogen fuel cell sealing member and the maximum contact stress are in positive correlation, the service life of the hydrogen fuel cell sealing member and the average internal stress are in negative correlation, and in the cross section design, the sealing performance of the sealing member when the sealing member is in pressure contact is enhanced by increasing the maximum contact stress, and the overall service life of the sealing member is improved by reducing the average internal stress;
the step 3) specifically comprises the following steps:
31 Acquiring an initial hydrogen fuel cell seal cross-sectional design;
32 Modifying and optimizing the initial scheme according to the optimization modification mode corresponding to the design principle;
33 Performing finite element simulation experiments on the optimized design scheme to obtain mechanical characteristics under the working condition of alternating temperature, if the design requirement is met, completing the design, otherwise, returning to the step 32);
in the step 32), the optimizing and modifying manner includes:
slowing the edge curvature to reduce stress concentration, taking an arch structure to enhance stability and improve overall internal stress distribution, and coordinating different contact area height differences to achieve multi-segment sealing contact under the same compression.
2. The method for designing a cross-section of a hydrogen fuel cell seal accounting for the effects of alternating temperatures according to claim 1, wherein each optimization modification mode specifically comprises the following means:
slowing down edge curvature: the curvature of the vertex angle of the cross section is reduced, so that the stress concentration phenomenon at the transition position of the vertex angle and the upper plane is improved, and meanwhile, the good contact state of the original model can be maintained;
altering the base angle shape: changing the bottom angle from the original right angle to a round angle so as to relieve the material tearing phenomenon caused by stress concentration;
removing the inner space: the whole sealing piece adopts an arch structure, so that the average internal stress distribution of the whole sealing piece is improved, the internal stress at each position tends to be average, and the support at the two ends of the arch structure can improve the gesture stability of the sealing piece when being pressed;
coordinating different zone height differences: in order to achieve the two mechanical indexes of stress concentration and sealing performance, the sealing performance of the sealing element is not inhibited, the heights of different areas are adjusted, the real compression rate between the areas is changed, and the average internal stress of a specific area is effectively reduced on the premise that the contact stress is unchanged.
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