Method for encapsulating active material for negative pole of Li-ion secondary battery

A negative electrode active material and secondary battery technology, applied in battery electrodes, electrode manufacturing, circuits, etc., can solve problems such as incompleteness and uneven coating, and achieve high charge and discharge efficiency and good cycle performance

Inactive Publication Date: 2009-11-04
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a negative electrode active material coated lithium ion secondary battery in order to overcome the shortcomings of the coating layer of the negative electrode active material obtained by the existing method of coating the negative electrode active material of the lithium ion secondary battery is uneven and incomplete. The method, the coating layer of the negative electrode active material obtained by this method is uniform and complete

Method used

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  • Method for encapsulating active material for negative pole of Li-ion secondary battery
  • Method for encapsulating active material for negative pole of Li-ion secondary battery
  • Method for encapsulating active material for negative pole of Li-ion secondary battery

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Embodiment 1

[0034] This example illustrates the method of the present invention for coating the negative electrode active material of a lithium ion secondary battery.

[0035] 2 kg of median particle size D 50 Be 17.54 microns, d002 corrected value of crystallite interlayer distance 0.33650 nanometers, specific surface area is 3.2 square meters per gram of natural graphite in XQM variable frequency planetary ball mill, after ball milling in Nanjing Keyan Experimental Research Institute (high energy ball mill) for 1 hour, add 0.1 kg of polystyrene, 10 g of dilauroyl peroxide, and continued ball milling for 3 hours to obtain graft-coated natural graphite particles. The graft-coated graphite was carbonized at 1200° C. for 2 hours in a nitrogen atmosphere to obtain natural graphite with a carbonized coating layer. The median particle size D of the carbonized natural graphite of the coating layer 50 It is 17.23 microns, the corrected value of d002 is 0.33652 nanometers, and the specific surf...

Embodiment 2-6

[0042] The negative electrode active material of lithium ion secondary battery is coated according to the method of embodiment 1, and difference is, the negative electrode active material of being coated and its median diameter D 50 , crystallite layer spacing d002 value, specific surface area, the weight ratio of the initiator and its coating agent, the weight ratio of the coating agent and the negative electrode active material, heating conditions, and the median particle size D50 of the negative electrode active material after coating , Crystallite layer spacing d002, specific surface area. See Table 1 for specific differences.

[0043] Table 1

[0044] Example

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Abstract

The invention relates to a method for coating cathode active substance in a lithium iron secondary battery. The method comprises the following steps: a mixture containing the cathode active substance and coating agent is heated under the atmosphere of inert gases. The mixture also comprises an initiator and the initiator is the organic peroxide only containing the C, H and O. Due to the invention does not adopts the method of forming a coating layer on the cathode active substance by the coating agent using the physical mixing of the coating agent and the cathode active substance as well as the heat polymerization, but adopts the way of adding the initiator in the process of mixing the coating agent and the cathode active substance to form a coating layer on the cathode active substance by the coating agent under the moderate condition and completing the fixing and the grafting reaction at the same time; thus the caking phenomenon can not occur, furthermore, the even and complete cathode active substance of the coating layer is obtained through the direct carbonization and graphitization without breakage. The battery manufactured according to the cathode active substance has a high efficiency of charge and discharge at the first time and a better circulation performance.

Description

technical field [0001] The invention relates to a method for surface modification of the negative electrode active material of a battery, in particular to a method for coating the negative electrode active material of a lithium ion battery. Background technique [0002] Lithium-ion secondary battery refers to an ion battery composed of two compounds that can reversibly intercalate and deintercalate lithium ions as positive and negative electrodes. Because of its high specific energy, high working voltage, wide working temperature range, low self-discharge rate, long cycle life, no pollution, light weight, good safety performance, etc., it has a wide range of applications. [0003] Lithium-ion secondary battery generally comprises battery casing and the electrode group and electrolytic solution that are sealed in this battery casing; Said electrode group comprises positive pole, negative pole, and the separator between positive pole and negative pole; Described negative pole ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/04H01M4/58C01B31/02
CPCY02E60/10
Inventor 姜俊刚李科刘卫平
Owner BYD CO LTD
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