A kind of preparation method of low-temperature lithium iron phosphate power battery cathode slurry

A technology of lithium iron phosphate and positive electrode slurry, which is applied in the direction of battery electrodes, secondary batteries, nanotechnology for materials and surface science, etc., can solve the difficulties in the production process of lithium iron phosphate positive pole pieces, battery performance attenuation, organic Oxidative decomposition of electrolyte solution and other problems to achieve the effect of overcoming the problem of difficult bonding

Active Publication Date: 2016-11-16
福建博瑞特电机有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, after the lithium iron phosphate material is nano-sized, the surface area of ​​the material increases, the interaction between particles increases, and there is a serious agglomeration phenomenon. Process problems such as poor mutual dispersion of conductive additives and poor adhesion of pole piece coating
In addition, due to the high surface activity of nano-lithium iron phosphate particles, the organic electrolyte solution is prone to oxidative decomposition during the charging and discharging process of the battery, resulting in rapid degradation of battery performance.
Therefore, the use of nano-lithium iron phosphate cathode materials cannot improve the low-temperature charge and discharge performance of lithium iron phosphate batteries on the premise of maintaining good overall performance.

Method used

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  • A kind of preparation method of low-temperature lithium iron phosphate power battery cathode slurry
  • A kind of preparation method of low-temperature lithium iron phosphate power battery cathode slurry
  • A kind of preparation method of low-temperature lithium iron phosphate power battery cathode slurry

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Effect test

Embodiment 1

[0027] Positive electrode formula: electroactive material lithium iron phosphate, conductive agent is conductive carbon black Super-P and conductive graphite KS-6, binder is LA132 water-based binder, dispersion medium is deionized water, and various substances in the slurry The parts by weight are: lithium iron phosphate: Super-P: KS-6: LA132: water is 90:3:3:4:100.

[0028] Preparation of positive electrode slurry: first add LA132 binder, water and conductive agent to High shear dispersing emulsifier Medium emulsification and dispersion for 1.5 hours, and then gradually adding lithium iron phosphate powder for emulsification and dispersion for 3.5 hours, and finally a small amount of water is used to adjust the viscosity of the positive electrode slurry to the range of 4500 mPas.

[0029] Negative electrode formulation: the negative electrode active material is artificial graphite, the conductive agent is conductive carbon black Super-P, the binder is LA132 water-based binder, the...

Embodiment 2

[0032] Example 2 (comparative example)

[0033] Positive electrode formula: electroactive material lithium iron phosphate, conductive agent is conductive carbon black Super-P and conductive graphite KS-6, binder is LA132 water-based binder, dispersion medium is deionized water, and various substances in the slurry The parts by weight are: lithium iron phosphate: Super-P: KS-6: LA132: water is 90:3:3:4:100.

[0034] Preparation of positive electrode slurry: first add LA132 binder, water and conductive agent to High speed mixer Disperse in the medium for 1.5 hours, and then gradually add lithium iron phosphate powder for dispersion for 3.5 hours, and finally adjust the viscosity of the positive electrode slurry to the range of 4500 mPas with a small amount of water.

[0035] Negative electrode formulation: the negative electrode active material is artificial graphite, the conductive agent is conductive carbon black Super-P, the binder is LA132 water-based binder, the dispersion medium...

Embodiment 3

[0040] The lithium iron phosphate batteries prepared in Example 1 and Example 2 were tested for low-temperature discharge performance according to the national QC / T743-2006 "Lithium Ion Battery for Electric Vehicles" standard method. The lithium iron phosphate battery prepared by the high-shear dispersing emulsifier has a discharge capacity of 83.4% of the rated capacity at -20°C, and a discharge capacity of 50.9% of the rated capacity at -40°C. The lithium iron phosphate battery prepared with a high-speed mixer has a discharge capacity of 62.5% of the rated capacity at -20°C, and basically cannot discharge at -40°C.

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Abstract

The invention relates to a preparation method for a low-temperature lithium iron phosphate power battery cathode slurry. According to the preparation method, a micro-level lithium iron phosphate powder, a conductive agent, a binder and a dispersion medium are added into a high shear dispersing emulsifier according to a certain ratio, the equipment is started, so that the materials make high-speed motion at gaps between multiple layers of rotors and stators in the high shear dispersing emulsifier, strong hydraulic shearing and turbulent flows are formed, the materials are dispersed, and also comprehensive acting forces such as centrifugal extrusion, grinding, bumping and the like are generated , so that finally the materials are fully mixed, stirred and refined and reach the ideal requirement. During preparation of the cathode slurry, a part of the micro-level particles are further refined to form nano-level particles, a lithium battery cathode sheet with wide particle size distribution is prepared, and the low-temperature charging / discharging performances of a lithium iron phosphate power battery are improved.

Description

Technical field [0001] The invention relates to a method for preparing a low-temperature lithium iron phosphate power battery positive electrode slurry, and belongs to the technical field of lithium ion secondary batteries. Background technique [0002] Lithium-ion secondary batteries have attracted people’s attention due to their high voltage, no memory effect, high energy density, and good cycle performance. They have become a rapidly developing new generation of green high-energy rechargeable batteries, which have a wide range of applications and considerable development prospects. [0003] Lithium batteries using lithium iron phosphate as the cathode material have the advantages of high specific energy density, long cycle life, low self-discharge rate, no memory effect, environmental protection, reliable safety, good high temperature and high rate charge and discharge performance. Lithium iron phosphate battery is an ideal choice as a power battery for electric vehicles and a r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1391B82Y30/00B82Y40/00
CPCH01M4/1397H01M4/5825H01M10/0525Y02E60/10
Inventor 阮震中张豫南
Owner 福建博瑞特电机有限公司
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