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A method and equipment for preparing lithium iron phosphate electrode sheets using a double-drive screw machine

A lithium iron phosphate, dual-drive technology, applied in the direction of positive electrodes, battery electrodes, active material electrodes, etc., can solve problems such as unstable production process and quality, brittle lithium iron phosphate batteries, and affect continuous production, and achieve weather resistance Excellent, increased surface area, shortened transmission distance effect

Inactive Publication Date: 2018-04-06
TIANHUA INST OF CHEM MACHINERY & AUTOMATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since lithium iron phosphate is more difficult to disperse when it reaches the nanoscale, it is impossible to form a good conductive effect between nanoscale lithium iron phosphate particles. This method of manufacturing electrodes must remove the organic solvent due to the introduction of solvents. When carrying out industrial scale production When the quality is difficult to control
In particular, lithium iron phosphate electrodes manufactured by coating methods are brittle and easy to break, and electrode sheets are prone to powder drop problems, which affect continuous production
[0006] According to the above, the current preparation of lithium iron phosphate electrodes needs to go through processes such as lithium iron phosphate synthesis, carbon coating, dispersion, and coating. Due to the high sensitivity of lithium iron phosphate to process conditions, it is far greater than other current industrialized positive electrodes. materials, resulting in unstable production process and quality due to complex production process and multiple treatments

Method used

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  • A method and equipment for preparing lithium iron phosphate electrode sheets using a double-drive screw machine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 1) Prepare polyvinyl alcohol with grade 17-88 and water to make a polyvinyl alcohol aqueous solution with a concentration of 100g / l, add lithium carbonate, ferric chloride, and ammonium phosphate into the polyvinyl alcohol aqueous solution, and mix it in a high-speed mixer at 800rpm Stir at a high speed and disperse for 25 minutes to obtain a slurry. The molar ratio of Li, Fe, and P in the complex composed of lithium carbonate, iron chloride, and ammonium phosphate is 1.5:1:1, and the amount of polyvinyl alcohol is lithium carbonate, iron chloride , 8% of the total mass of ammonium phosphate;

[0039] 2) Add ammonium carbonate and chloroacetic acid to the slurry obtained in step 1), mix evenly, and pump into the main feeding port of the double-drive meshing co-rotating twin-screw machine. Both ends of the screw machine have driving motors, and the end is a servo torque motor. Auxiliary drive to form a high aspect ratio, high shear and high compression continuous reactor...

Embodiment 2

[0045] combined with figure 1 A schematic diagram of the double-drive screw machine used to prepare lithium iron phosphate electrode sheets is described. A double-drive screw machine for preparing lithium iron phosphate electrode sheets, including: 1-main drive motor; 2-main feeding port; 3-vacuum devolatilization device; 4-auxiliary feeding port; Servo torque motor; 7-dispersion thread element; 8-devolatization thread element; 9-shear carbonization thread element; 10-engaging thread element; 11-compression thread element; 12-reverse thread element. There are driving motors at both ends of the screw machine, and the servo torque motor at the end is used for auxiliary driving. Through the auxiliary driving of the servo torque motor, lithium iron phosphate is synthesized to carbonized and coated under the condition of high aspect ratio of 80-85 / 1. One-piece continuous preparation of plasticizing and forming electrode sheets, in which a sheet die is set between the compression t...

Embodiment 3

[0047] 1) Prepare polyvinyl alcohol with a grade of 17-99 and water to make a polyvinyl alcohol aqueous solution with a concentration of 200g / l, add lithium oxalate, ferric hydrogen phosphate, and diammonium hydrogen phosphate into the polyvinyl alcohol aqueous solution, and mix in a high-speed mixer Stir and disperse at a high speed of 1000rpm for 25 minutes to obtain a slurry. The molar ratio of Li, Fe, and P in the complex composed of lithium oxalate, iron hydrogen phosphate, and diammonium hydrogen phosphate is 1.5:1:1, and the amount of polyvinyl alcohol is lithium oxalate , 10% of the total mass of ferric hydrogen phosphate and diammonium hydrogen phosphate;

[0048] 2) Add ammonium carbonate and chloroacetic acid to the slurry obtained in step 1), mix evenly, and pump into the main feeding port of the double-drive meshing co-rotating twin-screw machine. Both ends of the screw machine have driving motors, and the end is a servo torque motor. Auxiliary drive to form a con...

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Abstract

The invention provides a method used for preparing lithium iron phosphate electrode slices using a double-driven screw machine, and belongs to the field of lithium iron phosphate battery. According to the method, the double-driven screw machine is used for forming a continuous reactor with high length-diameter ratio and high shearing; conductive fiber and a polymer with weather resistance are added, lithium iron phosphate net in a hydrogel network structure is delivered through a slice mould outlet directly so as to obtain the lithium iron phosphate electrode slices. Problems of lithium iron phosphate electrode slices prepared via filing coating, that powder falling of lithium iron phosphate electrode slices is easily caused, coating technology is difficult to control, and environment requirements are strict, are avoided; lithium iron phosphate electrode slice cost is reduced greatly; quality stability of the lithium iron phosphate electrode slices is ensured; and integrated continuous preparation from lithium iron phosphate synthesis, to carbonization coating, plasticizing, and forming of electrode slices is realized. The invention also provides the double-driven screw machine used for preparing the lithium iron phosphate electrode slices.

Description

technical field [0001] The invention relates to the field of lithium iron phosphate batteries, in particular to a method and equipment for preparing lithium iron phosphate electrode sheets by using a double-drive screw machine. Background technique [0002] With people's thirst for high-energy-density power sources, there is an urgent need for the development and application of cheap, safe, environmentally friendly and high-performance secondary batteries. At present, lithium-ion batteries have been widely welcomed by people because of their high specific energy, high specific power and good high-temperature performance. Olivine-type lithium iron phosphate, as a kind of positive electrode active material with good safety, low price and environmental friendliness, has attracted great attention. [0003] The methods for preparing lithium iron phosphate in the prior art include solid-phase method, co-precipitation method, hydrothermal method and solvothermal method. However, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1397
CPCH01M4/1397H01M2004/028Y02E60/10
Inventor 张国强马永寿于秀丽
Owner TIANHUA INST OF CHEM MACHINERY & AUTOMATION