Preparation method of positive electrode material lithium iron phosphate for high-compaction lithium ion battery

A technology of lithium-ion batteries and positive electrode materials, applied in battery electrodes, secondary batteries, chemical instruments and methods, etc., can solve the problems of a large amount of waste gas treatment costs, poor electrical properties of materials, environmental pollution, etc., to improve grinding efficiency, Excellent electrochemical performance, the effect of improving mass transfer and heat transfer rate

Active Publication Date: 2018-10-26
江西省金锂科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The application for invention records: This method proposes a simple process that can significantly increase the compaction density of lithium iron phosphate cathode materials, but the phosphorus source used in this method is ammonium-containing salts, and a large amount of ammonia gas will be generated during the synthesis process. It needs to invest a lot of waste gas treatment costs and cause pollution to the environment. In addition, the lithium iron phosphate prepared from iron oxide and ferric oxide as the iron source has poor electrical properties.

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  • Preparation method of positive electrode material lithium iron phosphate for high-compaction lithium ion battery
  • Preparation method of positive electrode material lithium iron phosphate for high-compaction lithium ion battery
  • Preparation method of positive electrode material lithium iron phosphate for high-compaction lithium ion battery

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Embodiment 1

[0045] Lithium carbonate (Li 2 CO 3 ) 63.36 kg, iron orthophosphate (FePO 4) 250.00 kg, lithium dihydrogen phosphate (LiH 2 PO 4 ) 18.79 kg, D50=2um metal iron powder 10.24 kg, glucose 19.00 kg, and polyethylene glycol 11.00 kg were placed in a dispersion kettle, and then 630 L of deionized water was added for dispersion. The dispersion time of the slurry was 1 hour, and then coarse grinding was carried out. The coarse grinding time is 3 hours, and the particle size D50 of the slurry after coarse grinding is controlled at 1-2um. Finally, fine grinding is carried out, and the fine grinding time is 4 hours. After fine grinding, the particle size D50 of the slurry is controlled at 500nm to obtain a homogeneous mixed slurry.

[0046] Then spray-dry the uniformly mixed slurry obtained, the spray-drying air inlet temperature is controlled at 240°C, and the air outlet temperature is controlled at 90°C to obtain a spherical precursor powder; then the precursor powder is tableted, g...

Embodiment 2

[0049] Lithium carbonate (Li 2 CO 3 ) 50.69 kg of iron orthophosphate (FePO 4 ) 200.00 kg, lithium dihydrogen phosphate (LiH 2 PO 4 ) 57.96 kg, D50=1um metal iron powder (purity ≥ 98.5%) 31.59 kg, glucose 18.5 kg, water-soluble phenolic resin 9.50 kg in a dispersion kettle, then add 550L of deionized water to disperse, and the slurry dispersion time is 2h , then carry out coarse grinding, the coarse grinding time is 1h, the slurry particle size D50 after coarse grinding is controlled at 1-1.5um, and finally fine grinding is carried out, the fine grinding time is 6h, the slurry particle size D50 after fine grinding is controlled at 400nm, and a uniform Quality mixed slurry.

[0050] Then the uniformly mixed slurry obtained is spray-dried, the spray-drying air inlet temperature is controlled at 280°C, and the air outlet temperature is controlled at 100°C to obtain a spherical precursor powder; then the precursor powder is tableted, granulated and densified. The pressure use...

Embodiment 3

[0053] Lithium carbonate (Li 2 CO 3 ) 38.02 kg, iron orthophosphate (FePO 4 ) 150.00 kg, lithium dihydrogen phosphate (LiH 2 PO 4 ) 101.44 kg, D50 = 1.5um metal iron powder (purity ≥ 98.5%) 55.30 kg, sucrose 19.00 kg, polyvinyl alcohol 5.00 kg, PVP 6.00 kg in a dispersion kettle, then add ethanol 520L for dispersion, slurry dispersion time for 2h, and then carry out coarse grinding, the coarse grinding time is 3h, the slurry particle size D50 after coarse grinding is controlled at 1.2~2um, and finally fine grinding is carried out, the fine grinding time is 5h, and the slurry particle size D50 after fine grinding is controlled at 600nm, obtaining Homogenously mix the slurry.

[0054] Then spray-dry the homogeneously mixed slurry. The spray-drying air inlet temperature is controlled at 220°C, and the air outlet temperature is controlled at 70°C to obtain a spherical precursor powder; The pressure used for tablet granulation was 80 MPa to obtain a granular precursor.

[005...

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Abstract

The invention provides a preparation method of a positive electrode material lithium iron phosphate for a high-compaction lithium ion battery. The preparation method comprises the following steps thatS1, a lithium source, a composite iron source composed of ferric pyrophosphate and metal iron powder, a phosphorus source and a carbon source are prepared according to a certain proportion and put into a dispersion kettle, a solvent is added for dispersion, coarse grinding and fine grinding to obtain uniformly-mixed slurry, and the slurry is subjected to mist spraying and drying to obtain spherical precursor powder; S2, the obtained precursor powder is tableted, granulated and densified to obtain a granular precursor; S3, the obtained granular precursor is sintered at a high temperature underthe protection of inert gas, and then naturally cooled to the room temperature and pulverized to obtain a high-compaction lithium iron phosphate product. According to the preparation method, the composite iron source is adopted, the density of the metal iron powder is high, and in cooperation of nanoscale ferric pyrophosphate, synthesized lithium iron phosphate has excellent electrochemical performance and higher tap density; the precursor powder obtained by mist spraying and drying is tableted, granulated and densified, and therefore the sintering production efficiency and the density of thelithium iron phosphate material are improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery materials, in particular to a preparation method of high-pressure compacted lithium-ion battery anode material lithium iron phosphate. Background technique [0002] The new subsidy scheme for new energy vehicles takes the energy density of the battery system as the subsidy standard, especially the subsidy for new energy buses is greatly different depending on the performance level of the power battery. Although the energy density of lithium iron phosphate single cells of many battery companies can reach about 140wh / kg, the energy density of battery systems after grouping mostly does not exceed 120wh / kg. This means that most of the models that have been declared can only receive the lowest subsidy standard, which severely discourages the enthusiasm of car companies to develop pure electric buses. This requires cathode material companies to develop higher-performance lithium iron phosph...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58H01M10/0525
CPCC01B25/45C01P2004/03C01P2004/61H01M4/5825H01M10/0525Y02E60/10
Inventor 谢香兰杨安臣肖水龙熊杜娟罗邵滨
Owner 江西省金锂科技股份有限公司
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