Preparation method of lithium iron phosphate as cathode material of lithium ion battery

A technology for lithium iron phosphate and lithium ion batteries, applied in the field of continuous preparation of lithium iron phosphate materials, can solve the problems of non-continuous discharge, long heating time, slow heat transfer, etc., to avoid huge waste of energy, good charging Discharge performance, effect of narrow particle size distribution

Inactive Publication Date: 2010-02-03
NINGBO YINGTEWEI NEW MATERIALS
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when used in actual production, there are problems such as long heating time, difficult control of stirring and reaction conditions, inability to continuously discharge materials, slow heat transfer, and high energy consumption.
The above problems are the key to the rapid realization of industrialized batch production of the liquid phase synthesis method.
For example, when using conventional hydrothermal technology to produce, the main energy consumption is used to repeatedly heat the reaction system and containers, resulting in a huge waste of energy
The inner wall of the large reactor is thicker, which limits the heat transfer and is also the main factor causing high energy consumption and unstable quality of the system

Method used

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  • Preparation method of lithium iron phosphate as cathode material of lithium ion battery

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[0021] The preparation method of lithium iron phosphate lithium ion battery cathode material of the present invention comprises the following steps: mixing the reaction liquid uniformly and pressurizing, then passing through an externally heated heat pipe, utilizing the continuous flow of the liquid in the heat pipe and heating outside the heat pipe to make the reaction The raw materials are mixed, the crystals are nucleated, and grow up during the flow process to realize the continuous synthesis of lithium iron phosphate material. At the end of the reaction, after the liquid is cooled, filtered, washed, and dried, the finished product of lithium iron phosphate is obtained.

[0022] Such as figure 1 Shown, the present invention specifically comprises the following steps:

[0023] 1) Dissolve the analytically pure soluble ferrous salt, phosphoric acid source, and lithium source compound in high-speed stirred pure water in the batching tank 1 under the protection of an inert gas...

Embodiment 1

[0036] 277.85g of analytically pure ferrous sulfate heptahydrate, 111.76g of industrial phosphoric acid with a concentration of 85%, and 41.94g of lithium hydroxide monohydrate were dissolved in 10Kg of pure water stirred at high speed in a batching tank under nitrogen protection to form 0.1M of the mixture. After the obtained mixed solution was stirred for 0.5 h, it was pressed into the heat pipe by a high-pressure pump. After the liquid is pressurized, the pressure is 5Kg / cm 2 . The inner diameter of the heat pipe is 5mm, the material is corrosion-resistant austenitic stainless steel, and the length of the heating constant temperature zone is 100 meters. The inside of the heating container outside the heat pipe is maintained at 140°C. The flow rate of the final outlet is adjusted to 4.089 ml / min with a regulating valve, and the calculation shows that the heating process of the liquid in the heat pipe is 8 hours. After the liquid passes through the heat pipe, it passes th...

Embodiment 2

[0038] 91.3Kg of analytically pure ferrous chloride and 103.9Kg of lithium dihydrogen phosphate were dissolved in 1000Kg of pure water stirred at high speed in a batching tank under the protection of argon to form a 1M mixed aqueous solution. After the obtained mixed solution was stirred uniformly for 5 hours, it was pressed into the heat pipe by a high-pressure pump. After the liquid is pressurized, the pressure reaches 15Kg / cm 2 . The inner diameter of the heat pipe is 25mm, and the material is corrosion-resistant austenitic stainless steel. The length of the heating constant temperature zone is 20 meters. The inside of the heating container is maintained at 200°C, and the flow rate of the final outlet is adjusted to 81.77 ml / min with a regulating valve. It can be calculated that the heating process of the liquid in the heat pipe is 2 hours. The liquid enters the cooling pipe through the regulating valve after passing through the heat pipe. The liquid in the cooling pipe...

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Abstract

The invention discloses a preparation method of lithium iron phosphate as a cathode material of a lithium ion battery, which comprises the following steps: uniformly mixing reaction liquid and pressurizing the reaction liquid; then enabling reaction raw materials to mix, carry out crystal nucleation and grow in a flowing process through an external heating heat pipe by utilizing the continuous flow of liquid in the heating pipe and the heating outside the heat pipe so as to continuously synthesize a lithium iron phosphate material; at the tail end of the reaction, cooling, filtering, washing and drying the liquid to obtain a finished lithium iron phosphate product. The invention can avoid large energy waste caused by repeated heating when a reaction kettle is utilized and is beneficial toenergy saving and environment protection. When the liquid flows in the heating pipe, the materials are uniformly mixed and have smaller grain size, narrow grain size distribution and high purity; andbecause of continuous production, the performance of the materials is extremely stable, thus the invention is suitable for industrial mass production.

Description

technical field [0001] The invention relates to a method for continuously preparing positive electrode materials for power lithium ion batteries, in particular, a method for continuously preparing lithium iron phosphate materials by utilizing the flow of high-pressure hydrothermal liquid. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) material is a new generation of lithium-ion battery cathode material, which has the advantages of abundant resources, low price, safety and stability under extreme conditions such as overcharge and overdischarge, good discharge platform characteristics, and high cycle life, and has become a recognized power battery at home and abroad. Excellent candidate material. A lot of research has been done on it at home and abroad, especially its synthesis process, doping characteristics, carbon coating method and so on. At present, more than 200 patents can be retrieved in China. In recent years, industries such as electric vehicles,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58C01B25/45
CPCY02E60/12Y02E60/10
Inventor 陈建锋曹利文
Owner NINGBO YINGTEWEI NEW MATERIALS
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