Adhesive, its preparation method and lithium ion secondary battery prepared thereby

A lithium-ion battery and adhesive technology, which is applied in the direction of adhesives, battery electrodes, adhesive types, etc., can solve problems such as insufficient adhesive force, water-based negative electrode sheet falling off, sticking rollers, etc., to promote mutual dissolution and sliding small effect

Inactive Publication Date: 2009-04-01
SHENZHEN BAK BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This is mainly due to the aging of the adhesive in the pole piece after a long time or the insufficient adhesive force at the beginning of making the pole piece, so that the active material and the current collector are separated, piercing the separator paper, and causing a short circuit
[0004] At present, the water-based negative pole pieces of lithium-ion batteries generally use SBR (natural rubber plus solvent) styrene-butadiene rubber) as the binder. And other issues

Method used

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  • Adhesive, its preparation method and lithium ion secondary battery prepared thereby
  • Adhesive, its preparation method and lithium ion secondary battery prepared thereby
  • Adhesive, its preparation method and lithium ion secondary battery prepared thereby

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0028] The preparation method of adhesive comprises the steps:

[0029] (1) Separately weigh oleic acid styrene-butadiene rubber and rosin styrene-butadiene rubber to carry out masticating separately, after oleic acid styrene-butadiene rubber and rosin styrene-butadiene rubber are in molten state, carry out mixing again, make it mix evenly;

[0030] (2) Add plasticizer diethylene glycol dibenzoate, large white oil, antioxidant 2,6-di-tert-butyl p-cresol and solvent naphtha 120 of weighing (seeing experimental examples 1-7 behind) , Stir at a temperature of 75-80°C for 5-6 hours to make it evenly mixed.

[0031] The preparation of negative electrode slurry: negative electrode slurry comprises graphite FSN-1, conductive agent SFG-6, tackiness agent, CMC (sodium carboxymethyl cellulose), water (H 2 O) as solvent, its preparation method comprises the steps:

[0032] The first step: Divide the solvent into two parts according to the ratio of 3:7, mix and stir with CMC respectivel...

experiment example 1

[0040] Adhesive ratio:

[0041] Oleic acid styrene butadiene rubber: rosin styrene butadiene rubber: plasticizer: white oil: antioxidant: solvent = 18: 14: 2.0: 1.5: 0.75: 100

[0042] Proportion of negative electrode slurry:

[0043] FSN-1 (graphite): SFG-6 (conductive agent): SBR: CMC: solvent = 100: 2.12: 4.23: 1.59: 94

[0044] According to the test results of negative electrode sheet and battery prepared by the method of above-mentioned embodiment:

[0045] figure 1 It is the 1C cycle discharge capacity curve of the 18650 battery made in Experimental Example 1 of the present invention.

[0046] figure 2 Experimental Example 1 of the present invention is the tensile test curve of the negative pole sheet made in the present invention. In order to make the test more accurate, the tensile test curves of three sample batteries prepared by the above method are shown in the figure.

[0047] image 3 It is the weight loss rate data of the negative electrode sheet made in ...

experiment example 2

[0049] Adhesive ratio:

[0050] Oleic acid styrene butadiene rubber: rosin styrene butadiene rubber: plasticizer: white oil: antioxidant: solvent = 16: 12: 1.9: 1.4: 0.65: 95

[0051] Proportion of negative electrode slurry:

[0052] FSN-1 (graphite): SFG-6 (conductive agent): SBR (adhesive): CMC: solvent = 99:2:4:1:92

[0053] The test results of the negative electrode sheet and the battery prepared according to the method of the above embodiment: the capacity retention rate after 100 cycles was 96.78%, the maximum pulling force in the pulling test was 0.393 Newton, and the weight loss rate of the electrode sheet was 20.14%.

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Abstract

The invention discloses an adhesive, a preparation method thereof and a lithium-ion secondary battery prepared by applying the adhesive, wherein, the adhesive comprises the following components according to parts by weight: 16-20 portions of synthetic styrene-butadiene rubber, 12-14 portions of natural styrene-butadiene rubber, 1.4-1.6 portions of mineral oil, 0.65-1.0 portion of antioxidant and 95-110 portions of solvent. Preferably, the synthetic styrene-butadiene rubber is oleic acid styrene-butadiene rubber, and the natural styrene-butadiene rubber is rosin styrene-butadiene rubber. The invention also discloses the preparation method of the adhesive and the lithium-ion battery using the adhesive. The negative pole piece is not easy to crack and fall stock, and the phenomenon of roll banding usually encountered by the negative pole is eliminated. The bonding strength between the sizing agent prepared by the SBR and a negative pole current collector (clutch gold) is significantly increased, the dosage is less than that of the common formulation and the compaction ratio of the pole piece is improved; the lithium battery prepared by the negative pole piece guarantees the gram capacity development of active substances (graphite), simultaneously has small internal resistance and excellent cycle performance, and can be charged and discharged repeatedly.

Description

technical field [0001] The invention relates to an adhesive for the negative electrode sheet of a lithium secondary battery, a preparation method thereof and a battery prepared by using the adhesive. Background technique [0002] Lithium-ion battery is a battery with large capacity, high power, and high discharge voltage, which is mainly used in small devices, especially mobile phones, laptop computers, and portable electric tools. Lithium-ion batteries are generally composed of battery cover components, battery casings, electrolytes, and battery cells wound by positive and negative pole pieces and separator paper. Wherein the positive electrode active material is evenly coated on the positive electrode sheet, and the negative electrode active material is correspondingly evenly coated on the negative electrode sheet. [0003] In recent years, the research and development of lithium-ion batteries have made gratifying achievements, especially the improvement of negative elect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J109/06H01M4/62
CPCY02E60/10
Inventor 黄伟鹏
Owner SHENZHEN BAK BATTERY CO LTD
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