WO2023092799A1

WO2023092799A1 - Method and apparatus for marking internal micro-structure of electrochemical apparatus

Info

Publication number: WO2023092799A1
Application number: PCT/CN2021/141820
Authority: WO
Inventors: 陈新虹; 冯笑
Original assignee: 苏州易来科得科技有限公司
Priority date: 2021-11-23
Filing date: 2021-12-28
Publication date: 2023-06-01
Also published as: CN113821942A; CN113821942B

Abstract

A method and apparatus for marking an internal micro-structure of an electrochemical apparatus, which method and apparatus are used for simulating and calculating the electrochemical performance of the electrochemical apparatus. The method comprises: firstly acquiring geometric distribution state information of positive electrode particles, negative electrode particles, diaphragms, positive electrode conductive agents, negative electrode conductive agents and electrolytes of at least a partial region of an electrochemical apparatus; then generating a two-dimensional or three-dimensional graph on the basis of the acquired geometric distribution state information; next, generating a background grid on the basis of the generated graph and by using grid generation software; then marking, by using grid nodes, the boundaries or coverage regions of the negative electrode particles, the positive electrode particles, the diaphragms, the positive electrode conductive agents, the negative electrode conductive agents and the electrolytes; and finally, acquiring coordinate information of at least some marked nodes. In the method, the interior of a battery is marked by means of the steps, coordinate information of grid nodes is obtained, and after the coordinate information of the grid nodes is substituted into an electrochemical model, a predicted battery performance that is more accurate than other marking methods can be obtained, and the calculation efficiency is higher.

Description

Method and apparatus for marking internal microstructures of electrochemical devices

technical field

The invention relates to the field of electrochemical devices, in particular to a method and a device for marking the internal microstructure of an electrochemical device.

Background technique

An electrochemical device refers to a battery that can be reused. After the battery is discharged, the active material in the battery can be activated by charging, and the battery can continue to be used. One of the electrochemical devices is a battery made of positive electrode current collector, positive electrode active material, negative electrode current collector, negative electrode active material, conductive agent, electrolyte, separator and other accessories. The mainstream representative of this structure is lithium ion Battery. Lithium-ion batteries are widely used in various fields such as automobiles, electronics, and energy storage because of their high energy density. In the battery design process, it is very important to evaluate the electrochemical characteristics of the battery in advance to design a battery that meets the needs. The current mainstream electrochemical stage models include: three-dimensional model, mesoscopic scale model, particle stacking model, etc. These models need to obtain the geometric distribution information inside the electrode sheet before calculation, so as to predict the electrochemical performance of the battery, so accurate It is very important to obtain the distribution information of the microscopic geometric structure inside the electrode sheet.

technical problem

In order to overcome the defects in the prior art and improve the accuracy and efficiency of numerical simulation, an embodiment of the present invention provides a method and device for marking the internal microstructure of an electrochemical device.

technical solution

In order to achieve the above object, the technical scheme adopted in the present invention is:

In a first aspect, a method for marking the internal microstructure of an electrochemical device is provided, comprising the following steps:

Obtaining geometric distribution state information of positive electrode particles, negative electrode particles, separators, conductive agents and electrolytes in at least a partial area of the electrochemical device;

Generate two-dimensional or three-dimensional graphics based on the obtained geometric distribution state information;

Based on the generated graphics, use grid generation software to generate background grids;

Mark negative electrode particles, positive electrode particles, separators, positive electrode conductors, negative electrode conductors and electrolyte boundaries or their coverage areas through grid nodes;

Get coordinate information for at least some of the marked nodes.

Through the above method, each component of the battery is marked through the grid, so that the electrochemical performance of the battery can be accurately calculated using the electrochemical settlement model. It is especially important that the positive electrode particles inside the current lithium battery are irregular in shape and have pores inside. This method marks the coverage or boundary of the positive electrode particles. It not only meets the requirement of calculation accuracy, but also saves calculation resources.

Preferably, the partial area is the area between adjacent positive electrode current collectors and negative electrode current collectors, including a positive electrode coating, a separator, and a negative electrode coating. The positive electrode coating is at least composed of positive electrode particles, positive electrode conductors, and electrolytes. The negative electrode coating is at least composed of negative electrode particles, negative electrode conductive agent and electrolyte. Selecting the area between adjacent positive and negative current collectors for marking can not only accurately calculate the performance of the entire battery, but also save the number of marked nodes and save computing resources.

Further, in the step of obtaining coordinate information of marked nodes, each positive electrode particle or negative electrode particle obtains coordinate information of no less than 5 marked nodes. The applicant found that when performing electrochemical settlement, each positive electrode particle or negative electrode particle must obtain coordinate information of at least 5 marked nodes, so that the electrochemical performance of the battery can be calculated relatively accurately.

Further, the positive electrode particles are aggregated primary positive electrode particles, and the negative electrode particles are negative electrode active material particles. Since the primary particles of the positive electrode are usually lithium salt particles, these particles will be agglomerated inside the battery. The applicant found that marking a single particle takes a considerable amount of time and is not conducive to subsequent calculations. However, marking the agglomerated particles is not as good as marking a single particle Accurate, but still able to accurately predict the electrochemical performance of the battery through the electrochemical model.

Preferably, the negative electrode particles are marked by grid nodes to mark the boundaries of the negative electrode particles, and the positive electrode particles, separator, conductive agent and electrolyte are marked by grid nodes of their coverage areas. For the boundary marking of negative electrode particles, such as graphite, silicon carbon and other carbon materials commonly used at present, they will not agglomerate in the electrolyte and appear as a single individual with clear and regular boundaries. Accurate overall coordinates can be obtained only by marking the boundaries information. As for the positive electrode particles, especially the lithium salt type positive electrode particles commonly used at present, because they will agglomerate into larger positive electrode particles in the electrolyte, these particles are irregular in shape and have pores. For convenience. Similarly, for separators, conductive agents and electrolytes, their irregular shapes are also suitable for marking by covering methods. Of course, if in some applications, the negative electrode material or other materials are agglomerated in the electrolyte, and the primary particles of the positive electrode are separated from each other, then the negative electrode material can also be marked by marking the coverage area, and other materials with clear boundaries can be marked by marking the boundary. particles or components.

Preferably, the boundary marking grid node of the negative electrode particle is the closest grid node to the outside of the boundary of the conductive agent particle. At present, some carbon materials such as graphite and silicon carbon are commonly used as negative electrode materials. The surface has outward protrusions, and the outer grid nodes are used for marking. Compared with the method of not distinguishing the inner and outer sides, only the grid nodes closest to the boundary are selected for marking. The solution results are more accurate.

Further, the geometric distribution state information of positive electrode particles, negative electrode particles, diaphragm, conductive agent and electrolyte of the electrochemical device is generated based on an algorithm or by scanning the real object with an electron microscope.

The geometric distribution state information inside the battery can be generated through software algorithms based on the material information used, or it can be made into a real object and then scanned by an electron microscope to generate it.

In another aspect, a device for marking the internal microstructure of an electrochemical device is also provided, the device includes a memory and a processor, at least one program instruction is stored in the memory, and the processor loads and executes the at least A program instruction to implement the method for marking the internal microstructure of an electrochemical device according to the first aspect.

Beneficial effect

The present invention has the following advantages:

1. The present invention uses grid software to mark the positive electrode particles, negative electrode particles, diaphragm, positive electrode conductive agent, negative electrode conductive agent and electrolyte respectively inside the battery, which improves the accuracy of the marking.

2. The present invention uses the coverage area to mark the particles or components with blurred boundaries, and only marks the boundary of the boundary particles or object particles or components, so that the electrochemical model can calculate more accurate results based on these marking information, And it can save computing resources.

3. For the negative electrode particles with surface protrusions, the present invention adopts the method of marking the closest outer node, and the obtained node information can be solved by an electrochemical model to obtain a more accurate prediction result.

Therefore, by marking the inside of the battery through the above steps of the present invention, the grid node coordinate information obtained, after being substituted into the electrochemical model, can obtain a more accurate prediction of battery performance than other marking methods, and the calculation efficiency is more efficient.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structure of the internal parts of the lithium battery marked with the background grid in the present invention;

Fig. 2 is an enlarged view of part A in Fig. 1 .

The reference signs of the above drawings: 1, positive electrode collector; 2, negative electrode collector; 11, positive electrode coating; 101, positive electrode particles; 21, negative electrode coating; 201, negative electrode particles; 31, positive electrode conductive agent; 32, Negative electrode conductive agent; 4. Electrolyte; 5. Diaphragm; 6. Grid.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Embodiment: As shown in Figure 1, it is a partial cross-sectional view of the interior of the battery generated by algorithm simulation, including a positive electrode current collector 1, a positive electrode coating 11, a separator 5, a negative electrode coating 21, and a negative electrode current collector 2 from top to bottom. , the positive electrode coating 11, the negative electrode coating 21 and the gaps of the separator 5 are filled with the electrolyte 4, wherein the positive electrode coating 11 is distributed with a positive electrode conductive agent 31, and the negative electrode coating 21 is distributed with a negative electrode conductive agent 32.

The positive electrode coating 11 includes positive electrode particles 101 coated and solidified on the positive electrode current collector. The positive electrode particles are secondary aggregates formed after the primary active particles of the positive electrode lithium salt are agglomerated. The negative electrode coating 21 includes a coating And solidify the negative electrode particles 201 on the negative electrode current collector, the negative electrode particles are negative electrode carbon material active particles. The positive electrode coating 11 at least further includes a positive electrode conductive agent 31 and an electrolyte 4 filled in pores of the coating. The negative electrode coating 21 at least further includes a negative electrode conductive agent 32 and an electrolyte 4 filled in the pores of the negative electrode coating.

With reference to Fig. 1 and Fig. 2, the method for marking the internal microstructure of the electrochemical device of the present invention at least includes the following steps:

Obtain the geometric distribution state information of the positive electrode particles, negative electrode particles, separator, positive electrode conductive agent, negative electrode conductive agent and electrolyte in the partial area between the adjacent positive and negative electrode sheets of the electrochemical device generated based on the algorithm, wherein the positive electrode particles are made of lithium The agglomerated particles of the positive electrode primary particles made of salt, and the negative electrode particles are carbon material active particles;

Generate two-dimensional graphics based on the obtained geometric distribution state information;

In the above step of generating graphics, the geometric distribution state information in the battery can also generate three-dimensional graphics.

Based on the generated graphics, use grid generation software to generate a background grid 6;

The negative electrode particle is marked by the grid node closest to the outside of the negative electrode particle 201 boundary, the positive electrode particle is marked by the positive electrode particle 101 coverage area, the separator is marked by the diaphragm coverage area, the positive and negative electrode conductors are marked by the positive and negative electrode conductors and the electrolyte coverage area is marked by the positive and negative conductive agent coverage area Electrolyte, the grid density is such that the number of grid nodes marked by each positive electrode particle or negative electrode particle is about 500 to 1000;

It should be noted that due to the difference in particle size and the fact that the positive electrode particles made of lithium salt are easy to agglomerate, the size of the particles inside the battery is different, and the nodes required to mark the particles are also different. In order to obtain enough Quantitative coordinate information can be substituted into the electrochemical model to obtain more accurate electrochemical performance prediction data, and the grid density can be adjusted with grid generation software to meet the minimum number of marked grid nodes required for each positive electrode particle or negative electrode particle . The applicant found that the selection of the number of nodes marked by a single particle should not be less than 5, and when the number of nodes marked by a single particle is less than 5, the prediction accuracy will have a large deviation. Therefore, it is appropriate to adjust the density of the background grid so that the number of labeled nodes for each positive electrode particle or negative electrode particle is between 500 and 10,000. It is understandable that the larger the number of nodes, the more accurate the performance prediction will be. However, when the number of nodes marked by a single particle is too large, for example, more than 100,000, the accuracy of the prediction will not be significantly improved. Instead, it will consume a lot of computing resources.

In addition, for the setting of the background grid, on the one hand, the number of marked nodes can be adjusted by adjusting the density of the background grid; Screen some representative marked nodes to achieve the purpose of screening a small number of marked nodes at typical positions for accurate prediction. This method can be realized by image processing software.

In addition, for electrolytes, conductive agents, and separators, the number of labeled nodes is based on the number of labeled nodes for positive and negative particles.

For the marking of positive and negative electrode particles, different material systems may have different particle properties. For example, single crystal positive electrode particles will not agglomerate. At this time, the boundary can be marked. However, from the microstructure point of view, the morphology of the separator, positive and negative electrode conductors, and electrolyte is still irregular, and it is more suitable to mark by covering the area.

Finally, get the coordinate information of all marked nodes.

Substituting the coordinate information obtained above into electrochemical models, such as three-dimensional models, mesoscale models, particle stacking models and other electrochemical models, and bringing in other physical quantity information, such as temperature, current density, potential and other information, can be passed A chemical model predicts the electrochemical performance of lithium batteries.

For the acquisition of coordinate information, as mentioned above, the coordinate information of all marked nodes can be obtained according to the needs, and the coordinate information of only some representative marked nodes can be selected for calculation.

A device for marking the internal microstructure of an electrochemical device, the device includes a memory and a processor, the memory stores at least one program instruction, and the processor loads and executes the at least one program instruction to realize the electrical A method for labeling the internal microstructure of chemical devices.

In the present invention, specific examples have been applied to explain the principles and implementation methods of the present invention, and the descriptions of the above examples are only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to this The idea of the invention will have changes in the specific implementation and scope of application. To sum up, the contents of this specification should not be construed as limiting the present invention.

Claims

A method for marking the internal microstructure of an electrochemical device, which is used for simulating and calculating the electrochemical performance of an electrochemical device, is characterized in that it includes the following steps

Obtaining geometric distribution state information of positive electrode particles, negative electrode particles, separators, positive electrode conductive agents, negative electrode conductive agents and electrolytes in at least a partial area of the electrochemical device;

Generate two-dimensional or three-dimensional graphics based on the obtained geometric distribution state information;

Based on the generated graphics, use grid generation software to generate background grids;

Mark negative electrode particles, positive electrode particles, separators, positive electrode conductors, negative electrode conductors and electrolyte boundaries or their coverage areas through grid nodes;

Get coordinate information for at least some of the marked nodes.
The method for marking the internal microstructure of an electrochemical device according to claim 1: it is characterized in that: the partial area is the area between the adjacent positive electrode current collector and negative electrode current collector, including positive electrode coating, diaphragm, negative electrode Coating, the positive electrode coating is at least composed of positive electrode particles, positive electrode conductive agent, and electrolyte, and the negative electrode coating is at least composed of negative electrode particles, negative electrode conductive agent, and electrolyte.
The method for marking the internal microstructure of an electrochemical device according to claim 1, characterized in that: in the step of obtaining coordinate information of marked nodes, each positive electrode particle or negative electrode particle obtains no less than 5 marked nodes coordinate information.
The method for marking the internal microstructure of an electrochemical device according to claim 1, characterized in that: the positive electrode particles are secondary aggregates after the positive electrode primary particles are aggregated, and the negative electrode particles are negative electrode active material particles.
The method for marking the internal microstructure of an electrochemical device according to claim 1, 3 or 4, wherein the marking method of the negative electrode particles is to mark the boundaries of the negative electrode particles through grid nodes, and the positive electrode particles, Separators, conductors, and electrolytes are labeled as mesh nodes marking the area they cover.
The method for marking the internal microstructure of an electrochemical device according to claim 5, characterized in that: the boundary marking grid node of the negative electrode particle is the closest grid node to the outside of the boundary of the negative electrode particle.
According to claim 1, the method for marking the internal microstructure of an electrochemical device is characterized in that: the geometric distribution state information of the positive electrode particles, negative electrode particles, diaphragm, conductive agent and electrolyte of the electrochemical device is based on an algorithm or The real object is scanned with an electron microscope.
A device for marking the internal microstructure of an electrochemical device, characterized in that the device includes a memory and a processor, at least one program instruction is stored in the memory, and the processor loads and executes the at least one The program instructions are used to realize the method for marking the internal microstructure of an electrochemical device as described in any one of claims 1 to 7.