Burdening technology for slurry used by nanometer ferrous phosphate lithium ion battery

A lithium iron phosphate, lithium ion battery technology, applied in battery electrodes, circuits, electrical components, etc., can solve problems such as the inability to fix solid content ingredients, the speed cannot achieve the dispersion effect, and the production quality is affected, and is conducive to automation. Continuous production, excellent electrochemical performance, and the effect of shortening batching time

Inactive Publication Date: 2012-02-15
HUNAN FENGYUAN YESHINE KINGCO NEW ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In the manufacturing process of lithium iron phosphate lithium ion battery, its slurry preparation is a very important link. The conventional batching method in the prior art is to mix active materials, conductive agents, binders, dispersants, solvents and other The additives go through several steps of dry mixing, glue making and wet mixing, and then stir with a mixer for a long time to make a mixed slurry. The disadvantage is that the stirring speed of the mixer does not exceed 50 rpm, because the speed is too slow If the dispersion effect is not enough, the slurry is prone to abnormal phenomena such as stratification and sedimentation during coating, and it needs to be stirred for a long time, resulting in high viscosity and instability of the slurry, and it is impossible to fix the solid content of the ingredients and the density of the subsequent coating surface. Uneven or even impossible to coat, eventually leading to low battery capacity, uneven distribution, high internal resistance, poor consistency, etc., affecting production quality and increasing production costs
Some people also use the method of adding a dispersant to uniformly disperse lithium iron phosphate in a solvent to form an excellent slurry, but it is not very effective for nano-lithium iron phosphate materials, and the dispersant is harmful to the performance of the battery. And no benefit, the more you add, the greater the impact, the most obvious is that the capacity of the battery decreases rapidly with the increase of dispersant

Method used

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  • Burdening technology for slurry used by nanometer ferrous phosphate lithium ion battery
  • Burdening technology for slurry used by nanometer ferrous phosphate lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Nano-lithium ferrous phosphate (with a particle size range of 1-100nm) is used as the positive electrode material, superfine carbon powder (SuperP) is used as the conductive agent, polyvinylidene fluoride (PVDF) is used as the binder, and nitrogen-methylpyrrolidone (NMP) is used as the Solvent, nano-lithium ferrous phosphate: superfine carbon powder: polyvinylidene fluoride: nitrogen methyl pyrrolidone The mass ratio is 94:3:3:100, and the solid content is fixed at 50% (that is: lithium ferrous phosphate, super The mass ratio of fine carbon powder, polyvinylidene fluoride and nitrogen methyl pyrrolidone is 100:100), and the positive electrode slurry of lithium ion battery is prepared.

[0023] The slurry preparation process is as follows:

[0024] (1) Mix and stir the binder and 40% (mass fraction) solvent for 120 minutes according to the conventional method to make a glue with a solid content of about 7% (that is: the mass content of the binder in the solvent is 7%), ...

Embodiment 2

[0032] Completely make the preliminary slurry according to the conditions of Example 1, the preliminary slurry is stirred and dispersed reciprocally between the mixing tank and the disperser for 70min; the linear speed of the disperser is 40m / s, and then defoaming, filtering, iron removal process to make slurry. Use a 500ml transparent glass cup to take the slurry, irradiate the slurry with a laser pointer, and observe through light transmission. A straight and bright beam of light can be observed in the solution, indicating that the dispersion is very uniform.

[0033] The viscosity of the slurry was tested to obtain a viscosity of 1, and the viscosity was tested after being left open for 24 hours in an environment with a dew point of -50°C, and the viscosity was measured to be 2, and the viscosity was tested after 48 hours, and the viscosity was obtained after 7 days. The obtained test results are listed in Table 1. It can be seen from Table 1 that the slurry has little chan...

Embodiment 3

[0036] Completely make the preliminary slurry according to the conditions of Example 1, the preliminary slurry is stirred and dispersed reciprocally between the mixing tank and the disperser for 60min; the linear speed of the disperser is 45m / s, and then defoaming, filtering, iron removal process to make slurry. Use a 500ml transparent glass cup to take the slurry, irradiate the slurry with a laser pointer, and observe through light transmission. A straight and bright beam of light can be observed in the solution, indicating that the dispersion is very uniform.

[0037] The viscosity of the slurry was tested to obtain a viscosity of 1, and the viscosity was tested after being left open for 24 hours in an environment with a dew point of -50°C, and the viscosity was measured to be 2, and the viscosity was tested after 48 hours, and the viscosity was obtained after 7 days. The obtained test results are listed in Table 1. It can be seen from Table 1 that the slurry has little chan...

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Abstract

The invention relates to a burdening technology for slurry used by a nanometer ferrous phosphate lithium ion battery. Nanometer ferrous phosphate lithium ion, conductive agent, binder and N-methyl pyrrolidone are prepared into primary slurry; the primary slurry is stirred and dispersed for 60-90 minutes in a reciprocating mode between a stirring pot and a dispersion machine to obtain the slurry used by the nanometer ferrous phosphate lithium ion battery; and the linear velocity of the dispersion machine is 35-45m / s. The slurry prepared with the burdening technology disclosed by the invention can be evenly dispersed. The viscosity of the slurry slightly changes with the extending of placing time, and performance is stable. The lithium ion battery prepared by the slurry has the advantages of excellent electrochemistry performance, high retention rate of capacity-grading volumes and low resistance.

Description

Technical field: [0001] The invention relates to a batching process of slurry for lithium ion battery of nano-lithium ferrous phosphate, belonging to the technical field of chemical power supply preparation. Background technique: [0002] In the manufacturing process of lithium iron phosphate lithium ion battery, its slurry preparation is a very important link. The conventional batching method in the prior art is to mix active materials, conductive agents, binders, dispersants, solvents and other The additives go through several steps of dry mixing, glue making and wet mixing, and then stir with a mixer for a long time to make a mixed slurry. The disadvantage is that the stirring speed of the mixer does not exceed 50 rpm, because the speed is too slow If the dispersion effect is not enough, the slurry is prone to abnormal phenomena such as stratification and sedimentation during coating, and it needs to be stirred for a long time, resulting in high viscosity and instability ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCY02E60/10
Inventor 罗朝晖金旭东唐联兴梁凯彭微微
Owner HUNAN FENGYUAN YESHINE KINGCO NEW ENERGY
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