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Optimization method for lithium ion battery cellulose diaphragm multi-scale structural model

A technology of cellulose diaphragm and lithium-ion battery, applied in design optimization/simulation, electrical digital data processing, material analysis using radiation diffraction, etc., can solve problems such as not many achievements, and achieve accurate finite element model Effect

Active Publication Date: 2018-09-04
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] At present, most of the research on lithium-ion separators aims to improve some aspects of the performance of the separator through modification. However, there are not many results in the study of the separator from the internal structure.

Method used

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  • Optimization method for lithium ion battery cellulose diaphragm multi-scale structural model
  • Optimization method for lithium ion battery cellulose diaphragm multi-scale structural model
  • Optimization method for lithium ion battery cellulose diaphragm multi-scale structural model

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Experimental program
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Effect test

Embodiment 1

[0043] Aiming at the microscopic scale, the optimization method of the microscale structure model of the lithium-ion battery cellulose separator includes the following steps:

[0044]S11. On a microscopic scale, the original proportion of microfibrils 1 is 40%, the original proportion of matrix 2 is 60%, and the original average angle of microfibrils 1 is 20 degrees. It is established that microfibrils 1 are wrapped by matrix 2 The finite element model of the thin-walled cylinder, the elastic modulus E1 of the model = 10.78Gpa is obtained through finite element simulation;

[0045] S12. Using the atomic force microscope and adopting the nano-indentation test method to measure the force-displacement curve of a single fiber, the actual elastic modulus E2 of the single fiber is obtained after data processing = 11.71Gpa;

[0046] S13, comparative analysis is carried out to model elastic modulus E1 and actual elastic modulus E2, The model needs to be optimized, the proportion of ...

Embodiment 2

[0051] Aiming at the mesoscale, the optimization method of the mesoscale structure model of the lithium-ion battery cellulose separator includes the following steps:

[0052] S21. At the mesoscale, observe with an environmental scanning electron microscope and obtain an environmental scanning electron microscope photo of the cellulose separator;

[0053] S22. Randomly select several groups of environmental scanning electron microscope photos of cellulose diaphragms, use image processing methods to extract the boundary contours of the cellulose diaphragms in the photos, and select one group with clear border contours to establish a finite element model of the cellulose diaphragm at the mesoscale, and obtain Original fiber density of cellulose separator = 60% and diameter = 0.77um;

[0054] S23. Obtain the elastic modulus E3=1.95Gpa of the model through finite element simulation;

[0055] S24. Use the tensile and compression material testing machine, adopt the national test sta...

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Abstract

The invention discloses an optimization method for a lithium ion battery cellulose diaphragm multi-scale structural model. The method includes the steps of: S11. under a microscale, according to the original proportion of microfibril and a matrix and the original angle of microfibril, establishing a thin-walled cylindrical finite element model with the microfibril wrapped by the matrix, and conducting finite element analogue simulation to obtain an elastic modulus E1 of the model; S12. utilizing an atomic force microscope and adopting a nanoindentation experimental method to measure a force displacement curve of single fiber, and performing data processing to obtain an actual elastic modulus E2 of single fiber; S13. subjecting the elastic modulus E1 of the model and the actual elastic modulus E2 to contrastive analysis, if the result of (E1-E2) / E2 is less than -5%, increasing the proportion of the microfibril in the finite element model or decreasing the angle of the microfibril; if the result of (E1-E2) / E2 is greater than 5%, increasing the proportion of the matrix in the finite element model or increasing the angle of the microfibril; and if the result of the absolute value of (E1-E2) divided by E2 is smaller than or equal to 5%, carrying out no optimization on the finite element model. The method provided by the invention establishes and optimizes the cellulose diaphragm structural model, and improves the model accuracy.

Description

technical field [0001] The invention relates to lithium-ion battery cellulose diaphragm technology, in particular to an optimization method for a multi-scale structure model of lithium-ion battery cellulose diaphragm. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high working voltage, long service life, no memory effect, green and safe, and are widely used in mobile phones and other electronic products, and the new energy vehicle industry represented by electric vehicles is developing rapidly . As one of the four key materials of lithium-ion batteries, the diaphragm is mainly used to isolate the positive and negative electrodes, prevent short circuits, and provide microporous channels for lithium ions to pass through. [0003] At present, commercial lithium-ion battery separators on the market are mostly polyolefin material separators, usually unidirectional or biaxially stretched single-layer polyethylene (PE), polypropylen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N23/20G01Q60/24G01N3/08G01N23/22G06F17/50
CPCG01N3/08G01N23/20G01N23/22G01Q60/24G06F30/23
Inventor 彭羽健刘旺玉谢卫规闫长媛党艳萍
Owner SOUTH CHINA UNIV OF TECH