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Method for optimizing formation step by using alternating-current impedance test

A technology of AC impedance and working steps, applied in the field of lithium-ion batteries, can solve the problems of lack of pertinence, inability to specifically judge the state of film formation, small current size for the first charging and no clear definition of charging time, etc., to improve the quality of film formation. , Accurately collect impedance spectrum characteristics and improve the effect of formation efficiency

Active Publication Date: 2020-05-08
东莞维科电池有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The chemical formation method in the above literature does not have a clear definition of the small current and charging time for the first charge, and cannot specifically judge the state of the film formation, and is not targeted

Method used

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  • Method for optimizing formation step by using alternating-current impedance test
  • Method for optimizing formation step by using alternating-current impedance test
  • Method for optimizing formation step by using alternating-current impedance test

Examples

Experimental program
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Embodiment 1

[0061] The present embodiment provides a method for optimizing the chemical process steps by means of AC impedance testing, the method comprising the following steps:

[0062] (1) LiCoO 2 , conductive carbon black and polyvinylidene fluoride are mixed in a mass ratio of 95:3:2, and N-methyl-2-pyrrolidone is used as a solvent. After fully stirring, it is coated on an aluminum foil to obtain a positive electrode sheet; then graphite, conductive carbon Black and styrene-butadiene rubber are mixed in a mass ratio of 96:2:2, and water is used as a solvent. After being fully stirred, it is coated on a copper foil to obtain a negative electrode sheet; then the positive electrode sheet, separator and negative electrode sheet are wound, liquid injected, and Encapsulating to obtain the lithium cobaltate-graphite system electric core;

[0063] (2) Take 6 lithium cobalt oxide-graphite system cells and put them on the formation cabinet, the formation temperature is 75°C, the formation pre...

Embodiment 2

[0075] The present embodiment provides a method for optimizing the chemical process steps by means of AC impedance testing, the method comprising the following steps:

[0076] (1) Mix nickel-cobalt lithium manganese oxide (NCM), conductive carbon black and polyvinylidene fluoride in a mass ratio of 96:2:2, use N-methyl-2-pyrrolidone as a solvent, and coat it on an aluminum foil after fully stirring Then, graphite, conductive carbon black and styrene-butadiene rubber are mixed in a mass ratio of 8.5:1.5:0.5, and water is used as a solvent. After fully stirring, they are coated on copper foil to obtain a negative electrode sheet; then the positive electrode sheet , separator and negative electrode sheet are wound, injected and packaged to obtain the nickel-cobalt lithium manganese oxide-graphite system electric core;

[0077] (2) Take 8 nickel-cobalt lithium manganate-graphite system batteries and put them on the formation cabinet, the formation temperature is 85°C, the formatio...

Embodiment 3

[0081] The present embodiment provides a method for optimizing the chemical process steps by means of AC impedance testing, the method comprising the following steps:

[0082] (1) LiCoO 2 , conductive carbon black and polyvinylidene fluoride are mixed in a mass ratio of 97:1.5:1.5, with N-methyl-2-pyrrolidone as a solvent, fully stirred and coated on an aluminum foil to obtain a positive electrode sheet; then graphite / silicon, Conductive carbon black and styrene-butadiene rubber are mixed at a mass ratio of 8:1:1, and water is used as a solvent. After fully stirring, they are coated on copper foil to obtain a negative electrode sheet; then the positive electrode sheet, separator and negative electrode sheet are wound and injected Liquid and encapsulation, obtain described lithium cobalt oxide-graphite system electric core;

[0083] (2) Take 6 lithium cobalt oxide-graphite system cells and put them on the formation cabinet, the formation temperature is 85°C, the formation pres...

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Abstract

The invention relates to a method for optimizing formation steps by using an alternating-current impedance test. The method comprises the following steps: (1) taking at least three battery cells manufactured by the same process, respectively charging under different currents, and carrying out formation; and (2) carrying out alternating-current impedance test on each battery cell to obtain an alternating-current impedance spectrum, and selecting the alternating-current impedance spectrum with an arc in a high-frequency region, so that the working step corresponding to the spectrum is the formation working step of battery cell optimization. According to the method, the formation current and time can be specifically determined in a targeted manner, the SEI film forming state is optimized, thefilm forming quality and the formation efficiency are greatly improved, and the overall performance of the battery is improved. The method is high in universality, does not need to deeply explore thefilm forming mechanism of the SEI film, belongs to nondestructive testing, and can accurately collect impedance spectroscopy characteristics. In addition, the method is simple to operate, short in required time and high in efficiency, and has a wide application prospect.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for optimizing chemical formation steps by using AC impedance testing. Background technique [0002] Lithium-ion batteries have been widely used in mobile phones, notebook computers and power tools in modern society. Customers have higher and higher requirements on the battery capacity and cycle safety performance of lithium-ion batteries. Using modern testing methods to study the performance of lithium-ion batteries is an important way to reduce battery costs and increase mileage. AC impedance spectroscopy is widely used in the analysis of positive and negative electrode materials of lithium-ion batteries, the study of lithium-ion deintercalation kinetic parameters, and interfacial reactions. It is a powerful tool for analyzing the performance of lithium-ion batteries. Based on the research of existing technologies, the typical AC impedance spectrum of l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/367G01R31/389H01M10/44
CPCG01R31/367G01R31/389H01M10/446Y02P70/50
Inventor 付奥张爱莲葛鸽孙梦婷朱坤庆计阳夏小勇陶德瑜
Owner 东莞维科电池有限公司