A kind of positive electrode of battery, its preparation method and lithium ion secondary battery

A cathode and battery technology, applied in the battery field, can solve problems such as unsatisfactory rate performance, poor cycle performance, and easy material loss.

Active Publication Date: 2016-09-07
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the technical problems of poor wettability, easy material drop, poor cycle performance and unsatisfactory rate performance of the high-energy-density cathode electrolyte in the prior art, the present invention provides a better pore size distribution, better wettability of the electrolyte, and is not easy to High energy density battery positive electrode with material dropping, good cycle performance, lower internal resistance, better rate performance and high-temperature storage performance, preparation method thereof, and lithium-ion secondary battery

Method used

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  • A kind of positive electrode of battery, its preparation method and lithium ion secondary battery
  • A kind of positive electrode of battery, its preparation method and lithium ion secondary battery
  • A kind of positive electrode of battery, its preparation method and lithium ion secondary battery

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preparation example Construction

[0028] The present invention also provides a method for preparing the positive electrode, which is characterized in that the method includes firstly attaching the first conductive material to the conductive substrate, then attaching the first active material layer on the first conductive material layer, and then carrying out the first pressing step. sheet, and then attach the second conductive material layer on the first active material layer, and then attach the second active material layer on the second conductive material layer, and then carry out the second sheeting, wherein, the second sheeting after the second sheeting The compacted density of the active material layer is lower than the compacted density of the first active material layer after the first tableting.

[0029] Preferably, the compacted density of the second active material layer is 0.01-0.5 g / cm lower than the compacted density of the first active material layer 3 , further preferably, the compacted density...

Embodiment 1

[0049] (1) Preparation of positive electrode

[0050] The purchased aluminum foil current collector with a width of 400 mm and a thickness of 15 microns is degreased and cleaned, and then etched by a high-pressure plasma corona machine to obtain an aluminum foil with increased surface tension.

[0051] Mix 750g of NMP, 10g of PVP powder and 20g of PVDF (polyvinylidene fluoride), then add 220g of conductive carbon black and stir evenly to obtain the first conductive paste, and evenly coat the first conductive paste on Both surfaces of the treated aluminum foil 1 are coated with a thickness of 2-3 μm on each side, and then vacuum-dried at 90° C. for 0.5 hour to obtain a first conductive material layer 2 with a thickness of about 4 μm attached to the conductive substrate.

[0052] Mix 2000g of NMP and 60g of PVDF, then add 50g of conductive carbon black and stir evenly, and finally add 2000g of lithium iron phosphate and stir evenly to obtain the first positive electrode slurry (...

Embodiment 2

[0061] Positive electrode S2 and battery S22 were prepared by the same method as in Example 1, except that the pressure of the first tablet of the first active material layer was 50 MPa, and the compacted density was 2.2 g / cm 3 the first active material layer. The pressure of the second tablet pressing of the second active material layer is 45 MPa, and the compaction seal is 2.15g / cm 3 the second active material layer.

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Abstract

The present invention provides a battery positive electrode and a preparation method thereof, and a lithium ion secondary battery. The positive electrode comprises a conductive substrate and a material layer coated on the conductive substrate surface, wherein the material layer comprises a first conductive material layer attached on the conductive substrate, a first active material layer attached on the first conductive material layer, a second conductive material layer attached on the first active material layer, and a second active material layer attached on the second conductive material layer, and the compact density of the second active material layer is lower than the compact density of the first active material layer. According to the present invention, characteristics of excellent pore size distribution, good electrolyte infiltration and material shedding resistance are provided, and the prepared battery has characteristics of good cycle performance, low internal resistance, excellent rate capability, excellent high temperature storage performance and high energy density.

Description

technical field [0001] The invention relates to the field of batteries, in particular, the invention relates to a positive electrode of a battery, a preparation method thereof and a lithium ion battery using the positive electrode. Background technique [0002] Lithium-ion batteries are currently widely used secondary batteries, which have the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, and no pollution. Widely used in electric tools, electric vehicles and other fields, it not only requires high energy density, long cycle life, good consistency, good safety, low cost, etc., but also requires high specific power and excellent high rate charge and discharge performance. [0003] The diffusion and transport of lithium ions in the positive electrode sheet is an important performance index to measure the charge and discharge performance of the battery rate. The open porosity in the positive electrode sheet determines the di...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/139H01M10/0525
CPCH01M4/13H01M4/139H01M4/366H01M4/624H01M10/0525Y02E60/10
Inventor 鲍添增张闪闪马爱丽
Owner BYD CO LTD
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