A three-dimensional reconstruction method and device for a proton exchange membrane fuel cell catalyst layer

Abstract

The present invention provides a three-dimensional reconstruction method and device for a catalyst layer of a proton exchange membrane fuel cell. The method comprises: obtaining structural parameters of the catalyst layer, calculating the volume fraction of each component through the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; constructing a carbon particle model according to the volume fraction of carbon particles, a preset carbon particle size, and a preset carbon particle overlap; obtaining a first pore point on the surface of the carbon particle, constructing a platinum particle site according to the volume fraction of the platinum particles, and obtaining an initial model; obtaining a second pore point adjacent to the carbon particle and the platinum particle, performing probability assignment and iterative generation of ionomers on the second pore point until the number of ionomers accounts for the volume fraction of the ionomers, and obtaining a three-dimensional catalyst layer structure. The present invention can solve the technical problems in the prior art that numerical reconstruction simply divides the catalyst layer structure into a solid phase and a pore phase, and the performance calculation research is inaccurate.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a three-dimensional reconstruction method and device for a catalyst layer of a proton exchange membrane fuel cell. Background Art

[0002] In proton exchange membrane fuel cells, the microstructure of the catalyst layer (CL) plays a vital role in the performance of the fuel cell. Clarifying the microstructure of CL is the prerequisite for studying the pore size and reaction transport process. In-depth research on the microstructure of CL and understanding its internal transport characteristics are of great significance for improving the performance and durability of proton exchange membrane fuel cells. Therefore, obtaining a three-dimensional model of proton exchange membrane fuel cell catalysts is crucial for the performance analysis and optimization of fuel cells.

[0003] In the prior art, the three-dimensional model of the proton exchange membrane fuel cell CL is usually obtained by experimental methods and numerical reconstruction methods. The experimental method is generally to analyze the CL sample through nano-imaging technology and obtain a two-dimensional image, and then perform three-dimensional reconstruction processing through software. However, this method has low resolution, it is difficult to analyze the distribution of CL components, and it is difficult to distinguish between the polymer phase and the carbon phase. It is also impossible to observe the dynamic changes in the mass transfer process, and the cost is high. The numerical reconstruction method generally divides the CL into a solid phase and a pore phase, and regards carbon, platinum and ionomers as solid phases, which can avoid the defects of the experimental method, and has high efficiency, and can realize the optimization research of different structural parameters. However, the constructed structure is too simple and can only simulate the diffusion and chemical reaction of the gas. It is impossible to deeply study the influence of the complex microstructure of the CL on the reaction and transport process, which leads to inaccurate performance calculation research. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a three-dimensional reconstruction method and device for the catalyst layer of a proton exchange membrane fuel cell, so as to solve the problem that the numerical reconstruction in the background technology simply divides the catalyst layer structure into a solid phase and a pore phase, and the performance calculation research is inaccurate.

[0005] In one aspect, the present invention provides a method for three-dimensional reconstruction of a catalyst layer of a proton exchange membrane fuel cell, the method comprising: Acquiring structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculating the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; Constructing a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size, and the preset carbon particle overlap; Acquire the first pore point on the surface of all carbon particles of the carbon particle model, and construct platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; In the initial model, the second pore points adjacent to the carbon particles and the platinum particles are obtained, and based on the preset ionomer point probability, the second pore points are probability assigned and ionomers are iteratively generated until the number of ionomers accounts for the ionomer volume fraction to obtain a three-dimensional catalytic layer structure.

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer is calculated through the structural parameters of the proton exchange membrane fuel cell catalyst layer, and the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers, and the volume fraction of each component can be effectively obtained so as to subsequently accurately simulate the internal structure and distribution of the catalyst layer; a carbon particle model is constructed according to the carbon particle volume fraction, a preset carbon particle size, and a preset carbon particle overlap; the first pore point on the surface of all carbon particles of the carbon particle model is obtained, and according to the platinum particle volume fraction, a platinum particle site is constructed on the surface of the carbon particle model to obtain to an initial model; in the initial model, second pore points adjacent to carbon particles and platinum particles are obtained, and based on a preset probability of ionomer points, probability assignment is performed on the second pore points and ionomers are iteratively generated until the number of ionomers accounts for the volume fraction of the ionomer, so as to obtain a three-dimensional catalytic layer structure, and different components are analytically reconstructed and the content and distribution of different components are controlled, so that the real structure of the catalytic layer can be truly restored, thereby ensuring the accuracy and integrity of the microstructure of the catalytic layer. The reconstruction process is more efficient and flexible, and a powerful tool is provided for studying the performance of catalytic layers with different structures, thereby solving the technical problems that numerical reconstruction simply divides the catalytic layer structure into a solid phase and a pore phase, and the calculation and research of the performance is inaccurate.

[0007] According to one aspect of the above technical solution, the structural parameters include the density of carbon particles, the density of platinum particles, the density of ionomers, the mass ratio of platinum to carbon, the mass ratio of ionomer to catalytic layer, platinum loading, and the thickness of the catalytic layer.

[0008] According to one aspect of the above technical solution, the steps of obtaining the structural parameters of the catalyst layer of the proton exchange membrane fuel cell, and calculating the volume fraction of each component in the catalyst layer of the proton exchange membrane fuel cell by the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers, specifically include: The volume fraction of platinum particles and the porosity of the catalytic layer are calculated according to the mass ratio of platinum to carbon, the mass ratio of the ionomer to the catalytic layer, the density of the carbon particles, the density of the platinum particles, the density of the ionomer, the thickness of the catalytic layer, and the platinum loading, and the formula is as follows: , , The carbon particle volume fraction and the ionomer volume fraction are calculated according to the porosity of the catalyst layer, the platinum-carbon mass ratio, the mass ratio of the ionomer to the catalyst layer, the density of the carbon particles, the density of the platinum particles, and the density of the ionomer. The formula is as follows: , , in, , and are the carbon particle volume fraction, platinum particle volume fraction and ionomer volume fraction, respectively. is the porosity of the catalyst layer, , and are the density of carbon particles, the density of platinum particles and the density of ionomer, respectively. , are the mass ratio of platinum to carbon, the mass ratio of ionomer to catalyst layer, is the platinum loading, is the thickness of the catalyst layer.

[0009] According to one aspect of the above technical solution, the step of constructing a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap specifically includes: A coordinate point is randomly selected in the calculation domain as the sphere center, and an initial carbon particle sphere with a preset carbon particle size is generated on the sphere center, wherein the preset carbon particle size is 24nm-40nm; Iteratively growing new carbon particle balls on the initial carbon particle balls, and calculating whether the overlap between the new carbon particle balls and the initial carbon particle balls is within a preset carbon particle overlap, wherein the preset carbon particle overlap is 0-15%; If yes, the new carbon particle ball is defined as the initial carbon particle ball, and new carbon particle balls are iteratively grown, and the overlapping degree determination step is repeated; If not, the new carbon particle ball is deleted.

[0010] According to one aspect of the above technical solution, after defining the new carbon particle ball as an initial carbon particle ball, continuing to iteratively grow new carbon particle balls, and repeating the overlapping degree determination step, it also includes: The construction of the carbon particle model is completed until the percentage of the number of coordinate points in all initial carbon particle balls to the total number of coordinate points in the entire calculation domain reaches the carbon particle volume fraction.

[0011] According to one aspect of the above technical solution, the steps of obtaining the first pore points on the surfaces of all carbon particles of the carbon particle model, constructing platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles, and obtaining the initial model specifically include: The first pore points on the surfaces of all carbon particles in the carbon particle model are obtained, and the first pore points are randomly selected to grow platinum particles until the percentage of the total number of platinum particles to the total number of the first pore points reaches the volume fraction of the platinum particles, completing the construction of the platinum particle sites and obtaining an initial model.

[0012] According to one aspect of the above technical solution, the steps of obtaining a second pore point adjacent to a carbon particle and a platinum particle in the initial model, assigning a probability to the second pore point and iteratively generating an ionomer based on a preset ionomer point probability until the number of ionomers reaches the ionomer volume fraction, and obtaining a three-dimensional catalytic layer structure specifically include: Obtaining a second pore point adjacent to a carbon particle and a platinum particle in the initial model, and randomly assigning a value to the second pore point to obtain a first assigned value; Determine whether the first assignment number is greater than a preset assignment number; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the first assignment number judgment step is repeated for the next second pore point.

[0013] According to one aspect of the above technical solution, the step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Taking the growth core as the center, assign different preset ionomer point probabilities to 18 directions in space, and re-randomly assign values ​​to the second pore points around the growth core to obtain the second assigned number; Determining whether the second assigned value is less than a preset ionomer point probability in the same direction; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the second assignment number judgment step is repeated for the next second pore point.

[0014] According to one aspect of the above technical solution, the step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Then the second pore point is selected as the growth core to iteratively generate the ionomer, and it is determined whether the growth point of the ionomer generated around the growth core coincides with the original carbon particles and platinum particles; If yes, the growth point is a growth point of a non-ionomer, and the growth point is deleted; If not, the ionomer continues to grow on the growth point until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure.

[0015] Another aspect of the present invention provides a three-dimensional reconstruction device for a proton exchange membrane fuel cell catalyst layer, the device is used to perform the three-dimensional reconstruction method for a proton exchange membrane fuel cell catalyst layer, the device comprises: A component determination module, used to obtain structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculate the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; A carbon particle model building module, used to build a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap; An initial model building module is used to obtain the first pore point on the surface of all carbon particles in the carbon particle model, and to build platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; A three-dimensional structure model building module is used to obtain the second pore points adjacent to the carbon particles and the platinum particles in the initial model, and based on the preset ionomer point probability, the second pore points are probability assigned and ionomers are iteratively generated until the number of ionomers reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of a three-dimensional reconstruction method of a proton exchange membrane fuel cell catalyst layer in Example 1 of the present invention; Figure 2 This is a structural block diagram of a three-dimensional reconstruction device for a proton exchange membrane fuel cell catalyst layer in the second embodiment of the present invention; Component symbol description: Component determination module 100, carbon particle model building module 200, initial model building module 300, three-dimensional structure model building module 400; The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0019] Embodiment 1 See also Figure 1 , shown is a three-dimensional reconstruction method of a proton exchange membrane fuel cell catalyst layer in a first embodiment of the present invention, including steps S10 to S13.

[0020] Step S10, obtaining structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculating the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; The structural parameters include the density of carbon particles, the density of platinum particles, the density of ionomers, the mass ratio of platinum to carbon, the mass ratio of ionomers to catalytic layers, the platinum loading, and the thickness of catalytic layers.

[0021] Furthermore, the volume fraction of platinum particles and the porosity of the catalytic layer are calculated according to the mass ratio of platinum to carbon, the mass ratio of the ionomer to the catalytic layer, the density of the carbon particles, the density of the platinum particles, the density of the ionomer, the thickness of the catalytic layer, and the platinum loading, and the formula is as follows: , , The carbon particle volume fraction and the ionomer volume fraction are calculated according to the porosity of the catalyst layer, the platinum-carbon mass ratio, the mass ratio of the ionomer to the catalyst layer, the density of the carbon particles, the density of the platinum particles, and the density of the ionomer. The formula is as follows: , , in, , and are the carbon particle volume fraction, platinum particle volume fraction and ionomer volume fraction, respectively. is the porosity of the catalyst layer, , and are the density of carbon particles, the density of platinum particles and the density of ionomer, respectively. , are the mass ratio of platinum to carbon, the mass ratio of ionomer to catalyst layer, is the platinum loading, is the thickness of the catalytic layer.

[0022] By way of example and not limitation, the structural parameters of the catalyst layer of a proton exchange membrane fuel cell can be determined through publicly published research and actual measurements. For example, the density of carbon particles, the density of platinum particles, and the density of ionomer are 1800 mg·cm -3 、21450mg·cm -3 , 2000mg·cm -3 .

[0023] It should be noted that by obtaining the structural parameters of the catalytic layer, the volume fraction of each component can be effectively calculated to ensure the accuracy of the distribution of each component in the subsequent construction of the internal structure and improve the accuracy of the model construction.

[0024] Step S11, constructing a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap; Specifically, a coordinate point is randomly selected in the calculation domain as the sphere center, and an initial carbon particle sphere with a preset carbon particle size is generated on the sphere center, wherein the preset carbon particle size is 24nm-40nm; Among them, the setting of the preset carbon particle size is based on the measurement results of the shape and size of the carbon particles in the actual catalytic layer.

[0025] Iteratively growing new carbon particle balls on the initial carbon particle balls, and calculating whether the overlap between the new carbon particle balls and the initial carbon particle balls is within a preset carbon particle overlap, wherein the preset carbon particle overlap is 0-15%; The preset carbon particle overlap is set to ensure that the carbon particles are interconnected to form a stable structure, while preventing excessive overlap from causing blockage of the pore channels.

[0026] If yes, the new carbon particle ball is defined as the initial carbon particle ball, and new carbon particle balls are iteratively grown, and the overlapping degree determination step is repeated; If not, the new carbon particle ball is deleted.

[0027] In addition, after defining the new carbon particle ball as the initial carbon particle ball, continuing to iteratively grow new carbon particle balls, and repeating the overlapping degree determination step, the method further includes: The construction of the carbon particle model is completed until the percentage of the number of coordinate points in all initial carbon particle balls to the total number of coordinate points in the entire calculation domain reaches the carbon particle volume fraction.

[0028] It should be noted that the accuracy of the carbon particle model can be effectively improved by randomly selecting a coordinate point in the calculation domain as the sphere center to generate a carbon particle sphere and defining the number of carbon particles by the carbon particle volume fraction.

[0029] Step S12, obtaining the first pore points on the surfaces of all carbon particles in the carbon particle model, and constructing platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; Specifically, the first pore points on the surfaces of all carbon particles in the carbon particle model are obtained, and the first pore points are randomly selected to grow platinum particles until the percentage of the total number of platinum particles in the total number of the first pore points reaches the volume fraction of the platinum particles, completing the construction of the platinum particle sites and obtaining the initial model.

[0030] It should be noted that platinum particles play a core catalytic role in the catalytic layer. According to the actual catalytic layer structure, their position must be on the surface of the carbon particles to ensure the formation of a good electron conduction channel with the carbon particles and to improve the efficiency of the catalytic reaction. Therefore, it is necessary to obtain the first pore point on the surface of the carbon particles to facilitate the growth of platinum particles.

[0031] In addition, when selecting the first pore point to grow platinum particles, the agglomeration of platinum particles is not considered. The coordinates of the first pore point on the surface of the carbon particle are obtained as a set, and the coordinate points equal to the total number of platinum particles are randomly selected to determine the position of the platinum particles on the surface of the carbon particle.

[0032] Step S13, obtaining the second pore points adjacent to the carbon particles and the platinum particles in the initial model, and based on the preset ionomer point probability, performing probability assignment on the second pore points and iteratively generating ionomers until the number of ionomers reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure.

[0033] Specifically, a second pore point adjacent to a carbon particle and a platinum particle is obtained in the initial model, and a value is randomly assigned to the second pore point to obtain a first assigned value; Determine whether the first assignment number is less than a preset assignment number; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the first assignment number judgment step is repeated for the next second pore point.

[0034] The step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Taking the growth core as the center, assign different preset ionomer point probabilities to 18 directions in space, and re-randomly assign values ​​to the second pore points around the growth core to obtain the second assigned number; Determining whether the second assigned value is less than a preset ionomer point probability in the same direction; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the second assignment number judgment step is repeated for the next second pore point.

[0035] In addition, the step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Then the second pore point is selected as the growth core to iteratively generate the ionomer, and it is determined whether the growth point of the ionomer generated around the growth core coincides with the original carbon particles and platinum particles; If yes, the growth point is a growth point of a non-ionomer, and the growth point is deleted; If not, the ionomer continues to grow on the growth point until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure.

[0036] It should be noted that ionomers play an important role in proton conduction and oxygen dissolution and diffusion in the catalytic layer. In the real catalytic layer structure, ionomers are unevenly covered on the surface of carbon balls or platinum particles. The method of probabilistic assignment and iterative generation of ionomers is used to generate unevenly distributed ionomers, which can better simulate the complex distribution of ionomers in the actual catalytic layer. The growth nucleus of the ionomer is the second pore point adjacent to the carbon particles and platinum particles. This choice is based on the study of the formation mechanism of ionomers in the actual catalytic layer. By identifying the second pore point, setting a reasonable preset assignment number, and randomly assigning the second pore point, the ionomer growth nucleus is determined. With the ionomer growth nucleus as the center, the probability of ionomer points is preset in 18 directions of space, and the second pore nodes around the growth nucleus are re-randomly assigned, so that ionomers can be randomly generated around the ionomer growth nucleus until the volume fraction of the ionomer reaches the ionomer volume fraction.

[0037] In addition, the method further comprises: By adjusting various parameters in the above steps, such as the preset carbon particle size, the preset carbon particle overlap, the preset assignment number, and the preset ionomer point probability, different spatial distributions are adjusted to generate catalyst layers with different three-dimensional structures.

[0038] In summary, the three-dimensional reconstruction method of the proton exchange membrane fuel cell catalyst layer in the above-mentioned embodiment of the present invention calculates the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer through the structural parameters of the proton exchange membrane fuel cell catalyst layer, and can effectively obtain the volume fraction of each component, so as to accurately simulate the internal structure and distribution of the catalyst layer later; construct a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap; obtain the first pore point on the surface of all carbon particles of the carbon particle model, and construct platinum particle sites on the surface of the carbon particle model according to the platinum particle volume fraction to obtain an initial model; in the initial model The second pore points adjacent to the carbon particles and the platinum particles are obtained in the model, and based on the preset ionomer point probability, the second pore points are probability assigned and ionomers are iteratively generated until the number of ionomers reaches the volume fraction of the ionomer, and the three-dimensional catalytic layer structure is obtained. By analyzing and reconstructing different components and controlling the content and distribution of different components, the real structure of the catalytic layer can be truly restored, ensuring the accuracy and completeness of the microstructure of the catalytic layer. The reconstruction process is more efficient and flexible, and provides a powerful tool for studying the performance of catalytic layers with different structures, thereby solving the technical problems that numerical reconstruction simply divides the catalytic layer structure into a solid phase and a pore phase, and the calculation and research of the performance is inaccurate.

[0039] Embodiment 2 See also Figure 2 , shown is a three-dimensional reconstruction device for a proton exchange membrane fuel cell catalyst layer in a second embodiment of the present invention, the device comprising: The component determination module 100 is used to obtain the structural parameters of the catalyst layer of the proton exchange membrane fuel cell, and calculate the volume fraction of each component in the catalyst layer of the proton exchange membrane fuel cell according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; A carbon particle model building module 200 is used to build a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap; An initial model building module 300 is used to obtain the first pore points on the surfaces of all carbon particles in the carbon particle model, and to build platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; The three-dimensional structure model building module 400 is used to obtain the second pore points adjacent to the carbon particles and the platinum particles in the initial model, and based on the preset ionomer point probability, perform probability assignment on the second pore points and iteratively generate ionomers until the number of ionomers reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure.

[0040] In summary, the three-dimensional reconstruction device of the catalyst layer of the proton exchange membrane fuel cell in the above-mentioned embodiment of the present invention can effectively obtain the volume fraction of each component through the component determination module, so as to accurately simulate the internal structure and distribution of the catalyst layer later; through the carbon particle model construction module, the initial model construction module and the three-dimensional structure model construction module, the different components are analyzed and reconstructed, and the content and distribution of different components are controlled, so as to truly restore the real structure of the catalyst layer, ensure the accuracy and integrity of the microstructure of the catalyst layer, and make the reconstruction process more efficient and flexible, so as to provide a powerful tool for studying the performance of catalyst layers with different structures, thereby solving the technical problems that the numerical reconstruction simply divides the catalyst layer structure into a solid phase and a pore phase, and the performance calculation research is inaccurate.

[0041] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0042] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A three-dimensional reconstruction method for a proton exchange membrane fuel cell catalyst layer, characterized in that: The method comprises: Acquiring structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculating the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; Constructing a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size, and the preset carbon particle overlap; Acquire the first pore point on the surface of all carbon particles of the carbon particle model, and construct platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; In the initial model, the second pore points adjacent to the carbon particles and the platinum particles are obtained, and based on the preset ionomer point probability, the second pore points are probability assigned and ionomers are iteratively generated until the number of ionomers accounts for the ionomer volume fraction to obtain a three-dimensional catalytic layer structure.

2. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 1, characterized in that: The structural parameters include the density of carbon particles, the density of platinum particles, the density of ionomers, the mass ratio of platinum to carbon, the mass ratio of ionomers to catalytic layers, the platinum loading, and the thickness of catalytic layers.

3. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 2, characterized in that: The steps of obtaining structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculating the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers, specifically include: The volume fraction of platinum particles and the porosity of the catalytic layer are calculated according to the mass ratio of platinum to carbon, the mass ratio of the ionomer to the catalytic layer, the density of the carbon particles, the density of the platinum particles, the density of the ionomer, the thickness of the catalytic layer, and the platinum loading, and the formula is as follows: , , The carbon particle volume fraction and the ionomer volume fraction are calculated according to the porosity of the catalyst layer, the platinum-carbon mass ratio, the mass ratio of the ionomer to the catalyst layer, the density of the carbon particles, the density of the platinum particles, and the density of the ionomer. The formula is as follows: , , in, , and are the carbon particle volume fraction, platinum particle volume fraction and ionomer volume fraction, respectively. is the porosity of the catalyst layer, , and are the density of carbon particles, the density of platinum particles and the density of ionomer, respectively. , are the mass ratio of platinum to carbon, the mass ratio of ionomer to catalyst layer, is the platinum loading, is the thickness of the catalytic layer.

4. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 3, characterized in that: The step of constructing a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap comprises: A coordinate point is randomly selected in the calculation domain as the sphere center, and an initial carbon particle sphere with a preset carbon particle size is generated on the sphere center, wherein the preset carbon particle size is 24nm-40nm; Iteratively growing new carbon particle balls on the initial carbon particle balls, and calculating whether the overlap between the new carbon particle balls and the initial carbon particle balls is within a preset carbon particle overlap, wherein the preset carbon particle overlap is 0-15%; If yes, the new carbon particle ball is defined as the initial carbon particle ball, and new carbon particle balls are iteratively grown, and the overlapping degree determination step is repeated; If not, the new carbon particle ball is deleted.

5. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 4, characterized in that: After defining the new carbon particle ball as the initial carbon particle ball, continuing to iteratively grow new carbon particle balls, and repeating the overlapping degree determination step, the method further includes: The construction of the carbon particle model is completed until the percentage of the number of coordinate points in all initial carbon particle balls to the total number of coordinate points in the entire calculation domain reaches the carbon particle volume fraction.

6. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 5, characterized in that: The steps of obtaining the first pore points on the surfaces of all carbon particles of the carbon particle model, constructing platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles, and obtaining an initial model specifically include: The first pore points on the surfaces of all carbon particles in the carbon particle model are obtained, and the first pore points are randomly selected to grow platinum particles until the percentage of the total number of platinum particles to the total number of the first pore points reaches the volume fraction of the platinum particles, completing the construction of the platinum particle sites and obtaining an initial model.

7. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 6, characterized in that: The steps of obtaining second pore points adjacent to carbon particles and platinum particles in the initial model, assigning probabilities to the second pore points and iteratively generating ionomers based on a preset ionomer point probability until the number of ionomers reaches the ionomer volume fraction, and obtaining a three-dimensional catalytic layer structure specifically include: Obtaining a second pore point adjacent to a carbon particle and a platinum particle in the initial model, and randomly assigning a value to the second pore point to obtain a first assigned value; Determine whether the first assignment number is less than a preset assignment number; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the first assignment number judgment step is repeated for the next second pore point.

8. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 7, characterized in that: The step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Taking the growth core as the center, assign different preset ionomer point probabilities to 18 directions in space, and re-randomly assign values ​​to the second pore points around the growth core to obtain the second assigned number; Determining whether the second assigned value is less than a preset ionomer point probability in the same direction; If yes, the second pore point is selected as the growth core to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure; If not, the second pore point is not selected as the growth core, and the second assignment number judgment step is repeated for the next second pore point.

9. The three-dimensional reconstruction method of the catalyst layer of a proton exchange membrane fuel cell according to claim 8, characterized in that: The step of selecting the second pore point as the growth nucleus to iteratively generate ionomers until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure specifically includes: Then the second pore point is selected as the growth core to iteratively generate the ionomer, and it is determined whether the growth point of the ionomer generated around the growth core coincides with the original carbon particles and platinum particles; If yes, the growth point is a growth point of a non-ionomer, and the growth point is deleted; If not, the ionomer continues to grow on the growth point until the percentage of the total number of ionomers to the total number of the second pore points reaches the ionomer volume fraction, thereby obtaining a three-dimensional catalytic layer structure.

10. A three-dimensional reconstruction device for a proton exchange membrane fuel cell catalyst layer, characterized in that: The device is used to perform the three-dimensional reconstruction method of the proton exchange membrane fuel cell catalyst layer according to any one of claims 1 to 9, and the device comprises: A component determination module, used to obtain structural parameters of a proton exchange membrane fuel cell catalyst layer, and calculate the volume fraction of each component in the proton exchange membrane fuel cell catalyst layer according to the structural parameters, wherein the volume fraction of each component includes the volume fraction of carbon particles, the volume fraction of platinum particles, and the volume fraction of ionomers; A carbon particle model building module, used to build a carbon particle model according to the carbon particle volume fraction, the preset carbon particle size and the preset carbon particle overlap; An initial model building module is used to obtain the first pore point on the surface of all carbon particles in the carbon particle model, and to build platinum particle sites on the surface of the carbon particle model according to the volume fraction of the platinum particles to obtain an initial model; A three-dimensional structure model building module is used to obtain the second pore points adjacent to the carbon particles and the platinum particles in the initial model, and based on the preset ionomer point probability, the second pore points are probability assigned and ionomers are iteratively generated until the number of ionomers reaches the ionomer volume fraction to obtain a three-dimensional catalytic layer structure.

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