Method for vacuum mixing and coating material for lithium ion battery anode slice

A lithium-ion battery and coating method technology, which is applied to battery electrodes, electrode manufacturing, circuits, etc., can solve problems such as uneven coating, low electronic conductivity, and difficult material accumulation

Inactive Publication Date: 2009-04-15
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But since LiFePO 4 Low tap density, low electronic conductivity and other shortcomings, how to coat to make a better pole piece requires a reasonable material ratio, mixing process and coating technology
At present, there are many methods of stirring technology. The traditional stirring technology will bring air into the slurry, causing problems such as uneven coating, poor dispersion, and pores on the surface of the pole piece. In addition, due to the low tap density of lithium iron phosphate It is not easy to accumulate materials, so it is particularly important to choose a reasonable stirring coating process

Method used

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  • Method for vacuum mixing and coating material for lithium ion battery anode slice
  • Method for vacuum mixing and coating material for lithium ion battery anode slice

Examples

Experimental program
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Effect test

Embodiment 1

[0011] Example 1: Weigh lithium iron phosphate, conductive agent (acetylene black: graphite weight ratio=1:4) and polyvinylidene fluoride in proportion of 85%: 5%: 10%, and use polyvinylidene fluoride: 1-methyl The mass ratio of 2-pyrrolidone is 1:10 to weigh 1-methyl 2-pyrrolidone. First dry polyvinylidene fluoride at 120°C for 2 hours, then mix polytetrafluoroethylene and 1-methyl 2-pyrrolidone under vacuum and stir for 4 hours; at the same time, mix lithium iron phosphate and conductive agent for 4 hours, ball milling speed is 400r / min, and then The mixture of the two was dried at 120°C for 2 hours and then added to the above-mentioned stirred slurry. The stirring speed was 16 rpm for the dispersing wheel and 19 rpm for the orbiting wheel. Stir under vacuum for 16h. Pour the slurry into a small coater several times at a coating speed of 6r / min and a drying temperature of 100°C to coat a single layer with a thickness of 11 μm and a double layer with a thickness of 20 μm. ℃...

Embodiment 2

[0012] Embodiment 2: Weigh lithium iron phosphate positive electrode material, conductive agent (acetylene black: carbon fiber weight ratio=1: 1) and binder polyvinylidene fluoride in proportion of 86%: 6%: 8%, with polyvinylidene fluoride : 1-methyl 2-pyrrolidone mass ratio was 1: 11.25 and weighed 1-methyl 2-pyrrolidone. First dry polyvinylidene fluoride at 80°C for 4 hours to remove water, then mix polytetrafluoroethylene and 1-methyl 2-pyrrolidone under vacuum and stir for 6 hours; at the same time, mix lithium iron phosphate and conductive agent for 6 hours, and the ball milling speed is 300r / min , and then the mixture of the two was dried at 100°C for 4 hours and then added to the above-mentioned stirred slurry. The stirring speed of the dispersing wheel was 18rpm, and that of the orbital wheel was 20rpm. Stir under vacuum for 12h. Pour the slurry into a small coating machine several times at a coating speed of 5r / min and a drying temperature of 80°C to coat a single la...

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Abstract

The invention provides a method for coating a lithium ion battery anode plate by vacuum stirring materials. The method comprises the following steps: first, a binder and a solvent are evenly mixed by a certain proportion to obtain an adhesive; the prepared mixture of lithium iron phosphate and a conductive agent are added to the prepared adhesive to obtain a mixed slurry with the viscosity of 1000-10000mPas by vacuum mixing and stirring the materials, and then the slurry is coated by a coating machine to obtain an anode material plate. On the one hand, the anode material, the conductive agent and the binder can be evenly mixed by vacuum stirring the materials; on the other hand, air which results in blistering phenomenon on the plate surface while coating is prevented from being introduced into the slurry by a stirring blade at high-speed rotation by vacuum stirring the materials, thus enhancing the coating volume, mass and density of the material as well as enhancing the specific capacity and the cyclical stability of the anode material of the electrode plate.

Description

1. Technical field: [0001] The invention relates to a vacuum stirring coating method for a positive electrode sheet of a lithium ion battery, in particular to a vacuum stirring coating method for a positive electrode sheet using lithium iron phosphate as the positive electrode material, and belongs to the technical field of battery electrode sheet processing. 2. Background technology: [0002] Lithium-ion batteries have developed rapidly since their commercialization in 1991. They are not only widely used in portable devices such as mobile phones, cameras, and notebook computers, but also listed as candidate power sources for electric vehicles, aerospace, military equipment, and energy storage devices. Lithium-ion battery cathode materials not only participate in electrochemical reactions as electrode materials, but also serve as a "reservoir" of lithium ions. Therefore, the research progress of cathode materials for lithium-ion batteries directly restricts the development o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/1397
CPCY02E60/12Y02E60/10
Inventor 姚耀春杨斌戴永年廖文明易惠华李永梅胡成林于逢捷梁风秦博
Owner KUNMING UNIV OF SCI & TECH
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