Lithium ion battery positive material, and positive electrode and battery thereof

A technology for lithium-ion batteries and cathode materials, which is applied in battery electrodes, secondary batteries, circuits, etc., and can solve problems such as unsatisfactory anti-over-discharge solutions for lithium-ion batteries

Active Publication Date: 2014-04-02
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the technical problem that the existing lithium-ion battery anti-over-discharge scheme is not ideal enough, the present invention provides a lithium-ion battery positive electro

Method used

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  • Lithium ion battery positive material, and positive electrode and battery thereof
  • Lithium ion battery positive material, and positive electrode and battery thereof

Examples

Experimental program
Comparison scheme
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Embodiment approach

[0032] Among them, the separator can be selected from various separators used in lithium-ion batteries known to those skilled in the art, such as polyolefin microporous membrane (PP), polyethylene felt (PE), glass fiber felt or ultrafine glass fiber paper or PP / PE / PP. As a preferred embodiment, the separator is PP / PE / PP.

[0033] The electrolyte contains lithium salt and non-aqueous solvent. The lithium salt can be lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium perfluorobutylsulfonate, aluminate One or more of lithium, lithium chloroaluminate, lithium fluorosulfonyl imide, lithium chloride and lithium iodide; the non-aqueous solvent can be γ-butyrolactone, ethyl methyl carbonate, methyl propyl carbonate , dipropyl carbonate, acid anhydride, N-methylpyrrolidone, N-methylformamide, N-methylacetamide, acetonitrile, N,N-dimethylformamide, sulfolane, dimethylsulfoxide, disulfite ...

Embodiment 1

[0038] (1) Preparation of positive electrode:

[0039] 80g of lithium iron phosphate with a maximum particle size of 4 microns (D 50 =0.5 μm), 10g Li 1.01 Ni 0.89 mn 0.1 o 2 , 10g of iron phosphate with a minimum particle size of 30 microns (D 50 =40 microns), 4g of polyvinylidene fluoride (PVDF), 5g of conductive agent SP (super conductive carbon black), 0.5g of dispersant polyvinylpyrrolidone (PVP) and 120g of N-methylpyrrolidone were added to the vacuum mixer Stir to form a homogeneous cathode slurry. The positive electrode slurry was evenly coated on both sides of an aluminum foil with a thickness of 16 microns, then dried at 150° C., rolled and cut to obtain a positive electrode sheet with a size of 453*40 mm.

[0040] (2) Preparation of negative electrode:

[0041] Add 50g of natural graphite, 1g of binder styrene-butadiene rubber latex (SBR), 0.5g of binder carboxymethyl cellulose (CMC), and 125g of deionized water into a vacuum mixer and stir to form a unifo...

Embodiment 2

[0045] Adopt the same method and steps as in Example 1 to prepare the positive electrode, negative electrode and battery, the difference is the configuration of the positive electrode slurry: 84g lithium iron phosphate, 5g Li 1.076 Ni 0.628 mn 0.624 o 2 , 3 g Li 2 mn 2 o 4 , 10g of iron phosphate with a minimum particle size of 30 microns, 4g of polyvinylidene fluoride (PVDF), 5g of conductive agent SP, 0.5g of dispersant polyvinylpyrrolidone (PVP) and 120g of N-methylpyrrolidone were added to the vacuum mixer Stir to form a homogeneous cathode slurry.

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Abstract

The invention provides a lithium ion battery positive material, a lithium ion battery positive electrode containing the positive material, and a battery containing the positive material. The positive material comprises a lithium iron phosphate positive active material and iron phosphate, and the primary particle size of the iron phosphate is not lower than 20mum. The over-discharge resistance capability of the battery made of the positive material comprising large-granule iron phosphate and the lithium iron phosphate positive active material is excellent; and after cells made in the invention discharge to 2.0V, the cells continuously discharge to near 0V, the decrease trend of a positive electrode potential curve tends to stability, the rise of a negative electrode potential curve is not too high (generally not higher than 1.5V), and the above two potential curves become closer or intersect at 0V. Over-discharge is prevented, the safety of the monomer cells is guaranteed, and the low-potential-energy or uncharged safe transport is realized.

Description

technical field [0001] The invention relates to a positive pole material of a lithium ion battery, a positive pole of a lithium ion battery and a battery prepared by using the positive pole material. Background technique [0002] Compared with other chemical power sources, lithium-ion batteries have many excellent properties, such as high energy density, long cycle life, high open circuit voltage, no memory effect, safety and pollution-free, etc. After nearly two decades of rapid development, lithium-ion batteries have been widely used in mobile phones, notebook computers, digital cameras and other fields. With the rise of global oil prices and the enhancement of people's awareness of environmental protection, both research institutions and enterprises are paying attention to the development of electric vehicles. Researchers generally believe that lithium-ion batteries are one of the most promising chemical power sources for electric vehicles. Compared with other mobile de...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/136H01M10/0525
CPCY02E60/122H01M4/136H01M4/364H01M4/5825H01M4/62H01M10/0525Y02E60/10
Inventor 田野周耀华
Owner BYD CO LTD
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