Process for preparing Lithium ionic cell electrode slurry using ultrasonic-mechanical raking combination method

A lithium-ion battery, mechanical stirring technology, applied in the direction of electrode manufacturing, etc., can solve the problems of battery cycle life reduction, electrode piece cracking, unsatisfactory effect, etc., to achieve battery internal resistance reduction, increase utilization rate, and improve high-power output characteristics Effect

Pending Publication Date: 2007-09-19
BEIJING XIANGAO TIANZHU TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the particles of commonly used conductive agent carbon black or acetylene black are very small, generally around 50nm, it is easy to form agglomerated particles, and the serious agglomeration of conductive agent particles often leads to cracking of the coated electrode sheet during charging and discharging, and further Decrease the cycle life of the battery
Although the current pulping process can play a certain role in the dispersion of the conductive agent, the effect is not good
There are also some pulping processes that use ball milling and colloid milling to further disperse the conductive agent after the slurry is formed, but the effect is not ideal

Method used

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  • Process for preparing Lithium ionic cell electrode slurry using ultrasonic-mechanical raking combination method
  • Process for preparing Lithium ionic cell electrode slurry using ultrasonic-mechanical raking combination method
  • Process for preparing Lithium ionic cell electrode slurry using ultrasonic-mechanical raking combination method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Example 1 Preparation process of positive electrode slurry for lithium ion battery

[0016] As shown in Figure 1, add 100 kg of n-methylpyrrolidone and 3 kg of polyvinylidene fluoride into the barrel 2 from the feeding port 1, turn on the mechanical stirring motor 3, adjust the stirring speed to 300 rpm, and stir until polyvinylidene fluoride After the ethylene difluoride was completely dissolved, carbon black was added into material tank 2 and stirred for 1 hour. Then use the liquid pump 4 to send the above-mentioned mixed solution into the hydrodynamic ultrasonic generator 5 and carry out ultrasonic treatment. The outlet pressure of the liquid pump is 0.5MPa, and the liquid flow rate is 15m 3 , The ultrasonic sound intensity is 180dB. The ultrasonically treated mixed solution is sent back to the barrel 2 to continue stirring, so that the mixed solution circulates for 1.5 hours between the loops formed by the ultrasonic generator 5 and the barrel 2 . Finally, add LiM...

Embodiment 2

[0017] Example 2 Dispersion of conductive agent in electrode slurry

[0018] The electrode slurry prepared in Example 1 was coated on aluminum foil, and the surface morphology of the prepared coating was studied by scanning electron microscope (SEM). Figure 2 shows the SEM image at 200 times magnification, and Figure 3 shows the SEM image at 50,000 times magnification. It can be seen from Figure 2 that in the electrode active material LiMn 2 o 4 The surface is covered with a uniform layer of conductive material carbon black, indicating that carbon black and LiMn 2 o 4 Mix well. In Fig. 3, the large particles with regular shape are the electrode active material LiMn 2 o 4 , the small particles are carbon black, as can be clearly seen from the figure, each carbon black particle is separated, indicating that the carbon black does not agglomerate, which proves that the present invention can realize the high dispersion of the conductive agent in the electrode slurry .

Embodiment 3

[0019] Example 3 Preparation process of negative electrode slurry for lithium-ion batteries

[0020] Repeat the steps of Example 1, the difference is that the positive electrode material LiMn 2 o 4 Replaced with negative electrode material graphite.

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Abstract

The invention discloses a process for preparing lithium ion battery electrode paste by employing supersonic-mechanical stirring combining method, including following steps: binder and solvent are filled into a material tank to process mechanical stirring treatment with speed of 300 to 400 rpm, and after the binder is fully dissolved, conductive agent is added in, keeping on stirring for 0.5 to 1 hour; the mixed liquid is transferred into a hydrodynamic supersonic generator by a liquid pump for executing supersonic treatment, wherein the outlet pressure of the liquid pump is 0.1 to 2 MPa, the flowing speed is 1 to 40 m, the sound intensity of the supersonic is 180 to 240 dB; the mixed liquid treated by supersonic is returned to the material tank for stirring, in this manner, the mixed liquid needs to be circulated between the supersonic generator and the material tank for 1 to 1.5 hours; at last, battery active material is added into the material tank, going on stirring for 1.5 to 2 hours, and then well-mixed electrode paste can be obtained. The invention principally employs the supersonic cavitation to disperse the agglomerate conductive agent particles in short time, and to prevent agglomeration again thereby realizing high dispersion of the conductive agent in the electrode paste.

Description

technical field [0001] The invention relates to a preparation process of lithium ion batteries, in particular to a process for preparing electrode slurry in the production of lithium ion batteries. Background technique [0002] In the production process of lithium-ion batteries, the preparation of electrode paste is the first step. At present, the pulping process commonly used at home and abroad is to add electrode active materials, conductive agents, binders, binder solvents, etc. into the mixing tank in a certain proportion, and use mechanical stirring to mix the electrode slurry evenly. Since the particles of commonly used conductive agent carbon black or acetylene black are very small, generally around 50nm, it is easy to form agglomerated particles, and the serious agglomeration of conductive agent particles often leads to cracking of the coated electrode sheet during charging and discharging, and further The cycle life of the battery is reduced. Although the current ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04
CPCY02E60/10
Inventor 史杨杨君索琦
Owner BEIJING XIANGAO TIANZHU TECH
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