Method for increasing safe performance of square lithium ion secondary battery

A technology of secondary battery and safety performance, applied in secondary batteries, secondary battery manufacturing, battery electrodes, etc., can solve the problems of metal lithium dendrites easily pierced through diaphragm batteries, low reliability, etc., to reduce battery positive and negative Opportunity for extreme short circuit, effect of improving cycle life and improving cycle performance

Inactive Publication Date: 2007-02-21
TIANJIN LISHEN BATTERY
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  • Summary
  • Abstract
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AI Technical Summary

Problems solved by technology

Negative electrode active material, conductive agent and binder (SBR) solution dissolved in sodium carboxymethyl cellulose are mixed to obtain a slurry, and then coated on both sides of the aluminum or copper electrode fluid with a coating machine. There is only a thin layer of diaphragm between the electrodes. The unevenness of the positive and negative electrodes or the dead zone of the negative electrode during the charging and discharging process of the battery will form metal lithium dendrites, which will easily pierce the diaphragm and cause safety problems caused by short circuit of the battery, and the reliability is low.

Method used

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  • Method for increasing safe performance of square lithium ion secondary battery
  • Method for increasing safe performance of square lithium ion secondary battery
  • Method for increasing safe performance of square lithium ion secondary battery

Examples

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Embodiment 1

[0026] The active material on the positive electrode is LiCoO 2 , which is evenly coated on the aluminum foil; the active material on the negative plate is graphite, which is evenly coated on the copper foil. It is improved according to the surface treatment method of the negative plate of the square lithium-ion secondary battery, and the specific steps are as follows: Al2O3 is added to the binder (Al2O3 99g, PVDF1g) solution of N-methylpyrrolidone, at a constant speed Stir for 4 hours to obtain a slurry, apply it evenly on the surface of the negative electrode, and let it stand for 60 seconds. The purpose is to fully integrate the binder of the inorganic oxide and the binder of the negative electrode material. Adhesion; drying at 110°C to obtain the negative electrode sheet, the cross section of the electrode sheet is as follows figure 1 As shown, the coating effect is very obvious. Then, the positive and negative electrodes and the diaphragm are wound as usual, and the ele...

Embodiment 2

[0028] The active materials of the positive and negative electrodes are the same as in Example 1. It is improved according to the surface treatment method of the lithium-ion secondary battery negative plate, and the specific steps are as follows: add aluminum oxide to the binder (aluminum oxide 95g, PVDF 5g) solution of N-methylpyrrolidone and stir at a constant speed The slurry was obtained in 4 hours, which was uniformly coated on the surface of the negative electrode, left to stand for 60 seconds, and dried at 110°C to obtain a negative electrode sheet. The cross section of the electrode sheet is as follows: figure 2 As shown, the coating effect is very obvious. Then, the positive and negative electrodes and the diaphragm are wound as usual, and the electrolyte is injected to assemble a square battery. The cycle performance curve is as follows: Figure 4 .

Embodiment 3

[0030] The active materials of the positive and negative electrodes are the same as in Example 1. It is improved according to the surface treatment method of the lithium-ion secondary battery negative plate, and the specific steps are as follows: adding aluminum oxide to the binder (aluminum oxide 90g, PVDF10g) solution of N-methylpyrrolidone and stirring at a constant speed for 4 hour to obtain a slurry, which is uniformly coated on the surface of the negative electrode, left to stand for 60 seconds, and dried at 110°C to obtain a negative electrode sheet. The cross section of the electrode sheet is as follows: image 3 As shown, the coating effect is very obvious. Then, the positive and negative electrodes and the diaphragm are wound as usual, and the electrolyte is injected to assemble a square battery. The cycle performance curve is as follows: Figure 4 .

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Abstract

The battery is composed of anode of composite oxides containing lithium, cathode of carbon material with lithium being embedded, winded diaphragm of polyethylene, and injected electrolyte. Characters are that inorganic oxide coating is painted on surface of cathode. Mixing inorganic oxide and cementing material prepare the inorganic oxide coating. The specific producing steps are as following: stirring inorganic oxide and cementing material for 2-4 hours in even rate; painting the admixture onto surface of the cathode evenly; standing for 30-60 seconds, and drying at 80-110 deg.C. The invention reduces reaction between surface of active electrode and electrolyte, and self-discharge. Especially, when inner diaphragm is melted caused by abuse and high temperature, the inorganic oxide coating plays good insulation effect so as to reduce opportunity of short circuit, and raise safe reliability effectively.

Description

technical field [0001] The invention relates to a method for improving the performance of a lithium-ion battery, in particular to a method for improving the safety performance of a square lithium-ion secondary battery by processing electrode pole pieces during the production process of the lithium-ion secondary battery. Background technique [0002] At present, lithium-ion secondary batteries have the advantages of high voltage, high energy density, and low self-discharge, and are usually used as power sources for portable electronic devices. With the development of light weight electronic equipment, higher requirements are put forward for its power supply. Under such circumstances, improving the capacity and safety of prismatic lithium-ion secondary batteries is the research direction of many scientific researchers. In order to further improve the performance of various aspects of the square lithium-ion secondary battery, researchers have made many improvements to the posi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/04H01M10/40H01M4/04H01M4/02H01M4/62
CPCY02E60/122Y02E60/10Y02P70/50
Inventor 李鹏高俊奎张绍丽周波
Owner TIANJIN LISHEN BATTERY
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