Contents of the Invention
Embodiment of the present application provides a performance analysis method, apparatus, equipment and storage medium of the fuel cell catalytic layer, which can be more realistic to simulate the microscopic morphology of the catalytic layer under different water distribution conditions, and correct the ECSA by introducing effective factors to reflect the negative impact of flooding on the activation of catalyst particles, so as to accurately evaluate the performance state of the fuel cell catalytic layer.
On the one hand, the present application embodiment provides a performance analysis method of the catalytic layer of a fuel cell, comprising:
Construct a numerical model of the catalytic layer based on the scanned image of the catalytic layer;
Based on the numerical model, the hydrodynamic behavior of lattice Boltzmann method is used to simulate the solid phase distribution data and the flow characteristic data of liquid water, and the flow characteristic data of liquid water include the characteristic data of liquid water migration and redistribution in the catalytic layer.
Based on the flow characteristic data of liquid water, the diffusion rate of gases and the conductivity of charged substances in the numerical model are determined by using the pore scale model.
The activation specific surface area is determined based on the solid-phase distribution data and the effective factor based on local saturation;
Based on the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation, the performance parameters of the catalytic layer are obtained.
Optionally, the scanned image is a grayscale image acquired from the catalytic layer by a focused ion beam scanning electron microscope;
Construct a numerical model of the catalytic layer based on the scanned image of the catalytic layer, including:
Determine the distribution area of each component in the catalytic layer corresponding to the grayscale image;
Based on the distribution area corresponding to each component in the grayscale image, a numerical model of the catalytic layer is constructed in the preset calculation space.
Optionally, the effective factor is determined according to the following equation (1):
where β is the effective factor; S represents local saturation, characterizing the liquid water content of each local computing space based on the preset calculation space;
The activation specific surface area is determined based on solid-phase distribution data and effective factors based on local saturation, including:
Based on the solid-phase distribution data and the effective factor based on local saturation, the activation specific surface area is determined based on the following formula (2):
where aV represents the specific surface area of activation, SPt and V are solid-phase distribution data, where SPt represents the area covered by the polymer electrolyte of the catalyst particles and V represents the volume of carbon-loaded platinum.
Optionally, the methods also include:
Establish a three-dimensional macroscopic model of a single cell containing a catalytic layer;
Based on the 3D macroscopic model and the performance parameters of the catalytic layer, the performance curve of a single battery is determined, and the performance curve includes the relationship curve between battery voltage and battery average current density.
In another aspect, the present application embodiment provides a performance analysis apparatus for the catalytic layer of a fuel cell, comprising:
Building blocks, configured to perform numerical models of the catalytic layer based on scanned images of the catalytic layer;
The first determination module, configured to perform a numerical model based on the model, using the lattice Boltzmann method to simulate hydrodynamic behavior, to obtain solid phase distribution data and liquid water flow characteristic data; liquid water flow characteristic data include liquid water migration and redistribution characteristic data in the catalytic layer;
The second determination module, which is configured to perform flow characteristic data based on liquid water, uses the pore scale model to determine the diffusion rate of the gas and the conductivity of the charged substance in the numerical model;
The third determination module, configured to perform activation specific surface area determination based on solid-phase distribution data and effective factors based on local saturation;
The fourth determination module, which is configured to perform the performance parameters of the catalytic layer based on the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation.
Optionally, the scanned image is a grayscale image acquired from the catalytic layer by a focused ion beam scanning electron microscope;
The building blocks are configured to execute:
Determine the distribution area of each component in the catalytic layer corresponding to the grayscale image;
Based on the distribution area corresponding to each component in the grayscale image, a numerical model of the catalytic layer is constructed in the preset calculation space.
Optionally, a fifth determination module is also included, which is configured to execute: determine the effective factor according to the following formula (1):
where β is the effective factor; S represents local saturation, characterizing the liquid water content of each local computing space based on the preset calculation space;
The third determination module, configured to execute:
Based on the solid-phase distribution data and the effective factor based on local saturation, the activation specific surface area is determined based on the following formula (2):
where aV represents the specific surface area of activation, SPt and V are solid-phase distribution data, where SPt represents the area covered by the polymer electrolyte of the catalyst particles and V represents the volume of carbon-loaded platinum.
Optionally, the unit also includes:
Build a module that is configured to perform a three-dimensional macroscopic model of a single cell containing a catalytic layer;
The sixth determination module, which is configured to perform performance parameters based on the 3D macroscopic model and the catalytic layer, determines the performance curve of a single cell, which includes a curve between battery voltage and average battery current density.
On the other hand, the present application embodiment provides an apparatus comprising a processor and a memory, the memory stores at least one instruction or at least one program, at least one instruction or at least one program loaded by the processor and performs the performance analysis method of the fuel cell catalytic layer.
On the other hand, the present application embodiment provides a computer storage medium, the storage medium stores at least one instruction or at least one program, at least one instruction or at least one program loaded by the processor and executed to achieve the performance analysis method of the fuel cell catalytic layer described above.
The performance analysis method, apparatus, equipment and storage medium of the fuel cell catalytic layer provided in the embodiment of the present application has the following beneficial effects:
Based on the scanning image of the catalytic layer, a numerical model of the catalytic layer is constructed; based on the numerical model, the hydrodynamic behavior of the lattice Boltzmann method is used to obtain the solid-phase distribution data and the flow characteristic data of liquid water; the flow characteristic data of liquid water include the characteristic data of the migration and redistribution of liquid water in the catalytic layer; the flow characteristic data of liquid water are used to determine the diffusion rate of gases and the conductivity of charged substances in the numerical model by using the pore scale model The specific surface area of activation is determined based on the solid phase distribution data and the effective factor based on local saturation, and the performance parameters of the catalytic layer are obtained based on the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the activation specific surface area. This application can realistically simulate the microscopic morphology of the catalytic layer under different water distribution conditions, and correct the ECSA by introducing an effective factor to reflect the negative impact of flooding on the activation of catalyst particles, so that the performance state of the catalytic layer of the fuel cell can be accurately evaluated.
Specific embodiments
The following will be combined with the drawings in the embodiment of the present application, the technical solution in the embodiment of the present application is clearly and completely described, it is clear that the embodiment described is only a part of the embodiment of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without performing creative labor, are within the scope of protection of the present application.
It should be noted that the description and claims of the present application and the above-described drawings in the terms "first", "second", etc. are used to distinguish similar objects, and do not have to be used to describe a particular order or order. It should be understood that the data used in this way are interchangeable in appropriate circumstances, so that the embodiments of the present application described herein can be implemented in order other than those illustrated or described herein. Further, the terms "comprising" and "having" and any variation thereof is intended to cover an unequal inclusion, e.g., a process comprising a series of steps or units, methods, systems, products or services apparatus not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
FIG 1 is a schematic diagram of a PEMFC single cell structure provided in the present application embodiment, comprising a proton exchange membrane, an anode / cathode catalytic layer, a gas diffusion layer, anode / cathode runner and a bipolar plate. Among them, the gas diffusion layer is mainly made of carbon fiber, which acts as a conductive electron. The catalytic layer consists of four main elements: spherical graphite, which acts as a transfer of electrons; ionic polymers, which act as conductive protons; platinum catalysts, which provide electrochemical reaction sites; and pores, which facilitate the transport of reactants and products (such as oxygen, water vapor, and liquid water) of the anode and cathode.
Performance parameters directly related to fuel cell simulation experiments include permeability, porosity, conductivity, gas diffusion, and electrochemical active surface area (ECSA). For example, the catalytic layer needs to provide electron and proton transport pathways, accessibility of the reaction gas, high catalytic activity to HOR and ORR, and a sufficiently high ECSA. These parameters have corresponding special equipment and experimental methods that can be measured, but there are higher requirements for experimental equipment and site conditions. For the average researcher, it is difficult to have the corresponding experimental conditions and the cost is high. Therefore, it becomes meaningful to test the performance of the electrodes by means of simulation. It can assist in the conduct of fuel cell simulation experiments and improve the accuracy of simulation, so as to achieve a lot of time and money cost savings.
In addition, in the current fuel cell macro simulation study, the performance parameters of the porous catalytic layer are determined by consulting the literature or artificial parameters, and the matching degree with the actual case is not high, which ignores the impact of the change of the porous electrode pore scale level on the electrode performance under different working conditions. This application simulates the microscopic morphology of the catalytic layer under different working conditions through simulation, and then evaluates the performance parameters of the catalytic layer under the conditions, so as to improve the accuracy of fuel cell performance simulation experiments.
The following describes a specific embodiment of a performance analysis method of a fuel cell catalytic layer in the present application, FIG. 2 is a schematic diagram of a performance analysis method of a fuel cell catalytic layer provided in the present application embodiment, the present specification provides a method of operation such as an embodiment or flowchart, but based on conventional or uncompetitive labor may include more or less operating steps. The sequence of steps enumerated in an embodiment is only one of the many steps in the order of execution, does not represent a unique order of execution. Specifically, as shown in FIG. 2, the method may include:
In step S201, a numerical model of the catalytic layer is constructed based on the scanned image of the catalytic layer.
In the present embodiment, it is learned from experimental observations of hydrodynamic behavior in fuel cells that the kinetic behavior and transmission process of liquid water will have a significant impact on the performance and durability of each component of the PEMFC, especially for the cathodic catalytic layer. Therefore, understanding the two-phase transfer process in the various components of the PEMFC plays a crucial role in the water management and working performance of the battery.
Since the basic microscale transmission phenomena that occur in PEMFC porous electrodes cannot be observed by traditional macroscopic flow simulations, porosity scale simulation techniques need to be used to describe them more accurately, so the microstructure of these porous media such as GDL, MPL and CL needs to be reconstructed. Correct characterization of the microstructure of the PEMFC catalytic layer is a prerequisite for a full understanding of the transport phenomenon.
Thus, in the present embodiment, a high-precision focused ion beam scanning electron microscope (FIB-SEM) may be used to scan the catalytic layer sample, and then based on the scanned scanned image of the catalytic layer to construct a numerical model of the catalytic layer.
In other embodiments of the present application, 2D images may also be progressively acquired by X-ray tomography, the acquired images are processed, and a numerical model of the catalytic layer is constructed; alternatively, a stochastic four-parameter growth method (QuartetStructure Gencration Set, QSGS) stochastic reconstruction of the numerical model of the catalytic layer may also be used.
In an alternative embodiment, the scanning image is a grayscale image acquired by a focused ion beam scanning electron microscope of the catalytic layer; then, the above step S201 may include the following steps:
Determine the distribution area of each component in the catalytic layer corresponding to the grayscale image;
Based on the distribution area corresponding to each component in the grayscale image, a numerical model of the catalytic layer is constructed in the preset calculation space.
Specifically, the original grayscale image of the catalytic layer is processed and converted into an 8-bit image, and then the grayscale image is pixel segmented to distinguish the components in the catalytic layer: pores, carbon carriers, adhesives and the distribution area of the platinum catalyst, the gray pixel values corresponding to different components are different, wherein the gray pixel values corresponding to the carbon support are 70 to 100, the gray pixel values corresponding to the adhesive are 155, the gray pixel values corresponding to platinum are 255, and the gray pixel values corresponding to the pores are 0. Referring to FIG. 3, (a) is a schematic diagram of a grayscale image of a catalytic layer provided in the present embodiment of the application, (b) is a schematic diagram of a numerical model of a catalytic layer provided in the embodiment of the present application, the numerical model characterizes the geometry of the real catalytic layer, wherein the numerical model corresponds to the size of the preset calculation space of 200×200×200, and the reconstructed catalytic layer geometry has only two solid phases (carbon carrier and Pt) in the computing domain.
In step S203, based on the numerical model, the hydrodynamic behavior of lattice Boltzmann method is used to simulate the solid phase distribution data and the flow characteristic data of liquid water; the flow characteristic data of liquid water include the characteristic data of liquid water migration and redistribution in the catalytic layer.
The lattice Boltzmann method (LBM) is a mesoscopic simulation method that links macroscopic and microscopic models.
In the embodiment of the present application, the method is used to study the two-phase flow problem in the catalytic layer, simulating the hydrodynamic behavior in the catalytic layer, as shown in (c) in FIG. 3; thus, it is possible to obtain solid phase distribution data under different working conditions and liquid water flow characteristic data, different working conditions refers to different conditions of water distribution, different conditions of water content in the catalytic layer is different; liquid water flow characteristic data include liquid water in the catalytic layer migration and redistribution characteristic data.
In step S205, based on the flow characteristic data of liquid water, the diffusion rate of the gas and the conductivity of the charged substance in the numerical model are determined by using the pore scale model.
In the present embodiment, based on the flow characteristic data of liquid water, combined with pore scale model (pore scalemodel, PSM) to determine the content of different water and its distribution form, the diffusion rate of the gas and the conductivity of the charged substance in the numerical model.
In step S207, the activation specific surface area is determined based on the solid phase distribution data and the effective factor based on local saturation.
Among them, the activation specific surface area (ECSA) refers to the electrochemically active surface area, that is, the effective area involved in the electrochemical reaction. ECSA is usually based on solid-phase distribution data in the output of LBM, ecSA is defined as the ratio of the surface area of platinum particles covered by water to the volume of carbon-loaded platinum.
In the present embodiment of the application, it has been verified that the degree of contact between water and catalyst particles determines the size of ecsa, i.e., the water content and its distribution form will affect ECSA. Therefore, the present application introduces an effective factor to correct the ECSA when determining the ECSA to reflect the negative impact of flooding on the activation of catalyst particles.
In an alternative embodiment, the effective factor is determined according to the following formula (1):
where β is the effective factor; S represents local saturation, characterizing the liquid water content of each local computing space based on the preset computing space; for example, the preset computing space is divided into 8×8×8 local computing spaces, and the size of each local computing space is 25×25×25.
Correspondingly, the above steps S207 may include:
Based on the solid-phase distribution data and the effective factor based on local saturation, the activation specific surface area is determined based on the following formula (2):
where aV represents the specific surface area of activation, SPt and V are solid-phase distribution data, where SPt represents the area covered by the polymer electrolyte of the catalyst particles and V represents the volume of carbon-loaded platinum.
In step S209, based on the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation, the performance parameters of the catalytic layer are obtained.
In the embodiment of the present application, the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation, can be characterized as the performance parameters of the catalytic layer.
Further, the performance parameters of the above catalytic layer can be integrated and combined with the single-cell macro model to further determine the performance of the single battery. Among an alternative embodiment, the present application method further comprises:
Establish a three-dimensional macroscopic model of a single cell containing a catalytic layer;
Based on the 3D macroscopic model and the performance parameters of the catalytic layer, the performance curve of a single battery is determined, and the performance curve includes the relationship curve between battery voltage and battery average current density.
Among them, the relationship curve between battery voltage and battery average current density is used to characterize the performance of a single battery.
Specifically, the three-dimensional macroscopic model, as shown in (d) in Figure 3, consists of a membrane electrode assembly and an anode/cathode gas channels. After obtaining the performance parameters of the cathodic catalytic layer (diffusion rate of gas, conductivity of charged substances and specific surface area of activation), it is combined with the macroscopic model of single battery to further determine the performance of single battery. In this way, the time and money cost of the experiment can be greatly reduced, and the accuracy of the single-battery simulation experiment can be effectively improved.
In summary, after the three-dimensional numerical model of the catalytic layer is reconstructed based on the scanning image of the catalytic layer in the present application embodiment, the two-phase flow problem in the geometric morphology of the catalytic layer is studied by lattice Boltzmann method, the hydrodynamic behavior is simulated, and the solid phase distribution data and the flow characteristic data of liquid water are obtained, and secondly, the diffusion rate of the gas and the conductivity of the charged substance in the numerical model are determined by the pore scale model, and the ECSA is corrected by the effective factor to reflect the negative impact of flooding on the activation of catalyst particles. In this way, the catalytic capacity of the porous electrode can be more accurately characterized, and the performance parameters of the final catalytic layer can be combined with the three-dimensional macroscopic model of the single battery to further analyze the performance of the single battery, which can improve the accuracy of the fuel cell performance simulation experiment.
Embodiment of the present application further provides a performance analysis apparatus of a fuel cell catalytic layer, FIG. 4 is a structural schematic diagram of a performance analysis apparatus of a fuel cell catalytic layer provided in the embodiment of the present application, as shown in FIG. 4, the apparatus comprising:
Building block 401, configured to perform a numerical model of the catalytic layer based on the scanning image of the catalytic layer to construct;
The first determination module 402, configured to perform based on a numerical model, using the lattice Boltzmann method to simulate hydrodynamic behavior, to obtain solid phase distribution data and liquid water flow characteristic data; liquid water flow characteristic data include liquid water migration and redistribution characteristic data in the catalytic layer;
The second determination module 403, configured to perform flow characteristic data based on liquid water, using a pore-scale model, to determine the diffusion rate of the gas and the conductivity of the charged substance in the numerical model;
The third determination module 404, configured to perform the determination of the activation specific surface area based on the solid phase distribution data and the effective factor based on local saturation;
The fourth determination module 405, is configured to perform based on the characteristic data of liquid water migration and redistribution in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation, to obtain the performance parameters of the catalytic layer.
Optionally, the scanned image is a grayscale image acquired from the catalytic layer by a focused ion beam scanning electron microscope;
Building block 401, configured to execute:
Determine the distribution area of each component in the catalytic layer corresponding to the grayscale image;
Based on the distribution area corresponding to each component in the grayscale image, a numerical model of the catalytic layer is constructed in the preset calculation space.
Optionally, a fifth determination module is also included, which is configured to execute: determine the effective factor according to the following formula (1):
where β is the effective factor; S represents local saturation, characterizing the liquid water content of each local computing space based on the preset calculation space;
The third determining module 404, configured to execute:
Based on the solid-phase distribution data and the effective factor based on local saturation, the activation specific surface area is determined based on the following formula (2):
where aV represents the specific surface area of activation, SPt and V are solid-phase distribution data, where SPt represents the area covered by the polymer electrolyte of the catalyst particles and V represents the volume of carbon-loaded platinum.
Optionally, the unit also includes:
Build a module that is configured to perform a three-dimensional macroscopic model of a single cell containing a catalytic layer;
The sixth determination module, which is configured to perform performance parameters based on the 3D macroscopic model and the catalytic layer, determines the performance curve of a single cell, which includes a curve between battery voltage and average battery current density.
Embodiments of the apparatus and method embodiments in the present application are based on the same application idea.
Embodiments of the methods provided in the present application embodiment may be performed in a computer terminal, server, or similar computing device. Taking the server running as an example, FIG. 5 is a hardware block diagram of a fuel cell catalytic layer performance analysis method provided in the present application embodiment of the server. As shown in FIG. 5, the server 500 may produce relatively large differences due to different configurations or performance, may include one or more central processing units (Central Processing Units, CPU) 510 (processor 510 may include, but is not limited to, microprocessor NCU or programmable logic device FPGA and the like processing device), memory for storing data 530, one or more storage applications 523 or data storage medium 520 ( For example, one or one storage device in the amount of Shanghai). Wherein, the memory 530 and the storage medium 520 may be transient storage or persistent storage. The program stored in the storage medium 520 may include one or more modules, each module may include a series of instructions to the server operation. Further, the central processor 510 may be configured to communicate with the storage medium 520, performing a series of instruction operations in the storage medium 520 on the server 500. Server 500 may further include one or more power supplies 560, one or more wired or wireless network interfaces 550, one or more input and output interfaces 540, and / or, one or more operating systems 521, such as Windows, Mac OS, Unix, Linux, FreeBSD and the like.
Input and output interface 540 may be used to receive or transmit data via a network. Specific examples of the above networks may include a wireless network provided by the communication provider of the server 500. In one example, the input and output interface 540 includes a network adapter (Network Interface Controller, NIC), which may be connected to other network devices through the base station to communicate with the Internet. In one example, the input and output interface 540 may be a radio frequency (RadioFrequency, RF) module for communicating with the Internet by wireless means.
Those of ordinary skill in the art will appreciate that the structure shown in FIG. 5 is only illustrative, which does not qualify the structure of the above-described electronic device. For example, the server 500 may further comprise more or fewer components than shown in FIG. 5, or having a different configuration than shown in FIG. 5.
Embodiments of the present application further provide a storage medium, the storage medium may be disposed in the server to save a method embodiment of a fuel cell catalytic layer performance analysis method related to at least one instruction, at least one program, code set or instruction set, the at least one instruction, the at least one program, the code set or instruction set by the processor loaded and executed to achieve the performance analysis method of the fuel cell catalytic layer.
Alternatively, in the present embodiment, the storage medium may be located in at least one of the plurality of network servers on the computer network. Alternatively, in the present embodiment, the above-described storage medium may include, but is not limited to: a U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), a removable hard disk, a magnetic disk or a disc and the like may store program code and other media.
Embodiments of the performance analysis method, apparatus, apparatus and storage medium of the fuel cell catalytic layer provided by the above application can be seen, the present application constructs a numerical model of the catalytic layer by scanning the image based on the catalytic layer; based on the numerical model, the hydrodynamic behavior of the lattice Boltzmann method is used to simulate the hydrodynamic behavior, and the solid phase distribution data and the flow characteristic data of liquid water are obtained; the flow characteristic data of liquid water include the characteristic data of the migration and redistribution of liquid water in the catalytic layer; the flow characteristic data based on liquid water, using a pore scale model The specific surface area of activation is determined according to the solid phase distribution data and the effective factor based on local saturation, and the performance parameters of the catalytic layer are obtained based on the characteristic data of the migration and redistribution of liquid water in the catalytic layer, the diffusion rate of the gas, the conductivity of the charged substance and the specific surface area of activation. This application can realistically simulate the microscopic morphology of the catalytic layer under different water distribution conditions, and correct the ECSA by introducing an effective factor to reflect the negative impact of flooding on the activation of catalyst particles, so that the performance state of the catalytic layer of the fuel cell can be accurately evaluated.
It should be noted that the above-mentioned sequence of embodiments of the present application is only for description and does not represent the advantages and disadvantages of the embodiments. And the above specific embodiments of the present specification are described. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims may be performed in a different order than in the embodiments and still the desired result may be achieved. Further, the process depicted in the drawings does not necessarily require a particular order shown or a continuous sequence to achieve the desired result. In certain embodiments, multitasking and parallel processing may also be or may be advantageous.
Each embodiment in the present specification is described in a progressive manner, the same similar parts between each embodiment can be seen with each other, each embodiment focuses on the differences with other embodiments. In particular, for the device embodiment, because it is substantially similar to the method embodiment, the description is relatively simple, and the relevant points can be described in part of the method embodiment.
Those of ordinary skill in the art will appreciate that all or part of the steps to implement the above embodiments may be completed by hardware, or may be completed by programs to instruct related hardware, the program may be stored in a computer-readable storage medium, the storage medium referred to above may be read-only memory, disk or optical disk and the like.
The foregoing is only a preferred embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection of this application.