Power lithium ion battery

A lithium-ion battery and power technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of lithium-ion battery charging and discharging performance not being able to achieve good performance, application limitations, electrolyte decomposition, etc. Rate capability, improving poor electrical conductivity, improving ionic conductivity

Inactive Publication Date: 2009-09-09
GUILIN JIUYI NEW ENERGY SCI & TECH CORP
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. With LiCoO 2 The commercial lithium-ion battery is a positive electrode and graphite is a negative electrode, but due to the strong oxidative Co + , it is easy to cause the electrolyte to decompose, causing the battery to explode, the safety performance is poor, and it cannot be used as a power source for electric vehicles
[0005] 2. With LiMn 2 o 4 Lithium-ion batteries with graphite as the positive electrode and graphite as the negative electrode have greatly improved safety performance, but due to LiMn 2 o 4 The capacity is low, the cycle life is poor, and it needs to be further developed as a power supply for electric vehicles
[0006] 3. With LiFePO 4 Lithium-ion battery with positive electrode and graphite material as negative electrode, LiFePO 4 It is a new type of lithium-ion battery cathode material, its theoretical specific capacity is as high as 170mAh / g, LiFePO 4 The structural characteristics make it have excellent safety performance and thermal stability, high compatibility with the electrolyte, especially excellent cycle stability, life can reach more than 8000 times; and graphite materials due to their high specific capacity, voltage Due to the advantages of stable platform and other advantages, it is a negative electrode material commonly used in commercial lithium-ion batteries. However, lithium-ion batteries with graphite as the negative electrode will produce obvious capacity fading after 500 charges and discharges. Therefore, with a relatively low cycle life Graphite and LiFePO 4 The charge and discharge performance of lithium-ion batteries made of materials cannot achieve better performance.
However, since LiFePO 4 and Li 4 Ti 5 o 12 The problem of poor conductivity limits their application

Method used

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Examples

Experimental program
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Effect test

preparation example Construction

[0030] 1) Preparation of positive electrode

[0031] 85% to 95% (mass) of nano-sized LiFePO 4 / C, 2% to 10% (mass) of Super P (super conductive carbon black), 2% to 10% (mass) of PVDF (polyvinylidene fluoride) and an appropriate amount of N-methylpyrrolidone (NMP). Positive electrode slurry: using aluminum foil as the current collector, apply the positive electrode slurry evenly on the aluminum foil with a coating machine, and dry it at 70°C±5°C to make a pole piece, and cut the pole piece into a length of 337mm and a width of 22.5mm positive electrode with a thickness of 180μm±10μm.

[0032] 2) Preparation of negative electrode

[0033] 85% to 95% (mass) of nanoscale Li 4 Ti 5 o 12 / C, 1% to 4% (mass) of Super P (super conductive carbon black), 3% to 8% (mass) of SBR (carboxylated styrene-butadiene latex) and 1% to 4% of CMC (carboxymethyl fiber Sodium plain) was stirred to make a negative electrode slurry; using copper foil as a current collector, the negative electrode...

Embodiment 1

[0038] 1. LiFePO 4 / C and Li 4 Ti 5 o 12 Preparation of / C

[0039] 1. LiFePO 4 Preparation of / C:

[0040] Weigh 24.24g Fe(NO 3 ) 3 9H 2 O is placed in a 500ml beaker, add 200ml distilled water, stir to dissolve, then add 5.28g ascorbic acid, stir to dissolve to obtain a light green solution, and then add 6.92gH 3 PO 4 and 2.52g LiOH·H 2 O, stir and dissolve, then add 5.48g carboxymethyl starch, heat and stir at 80°C, starch gelatinization, Li + , Fe 2+ and PO 4 3+ Coexist in the macromolecular network of starch and disperse evenly to obtain uniform starch-based LiFePO 4 Continue heating and stirring the precursor solution until the water is evaporated to dryness to obtain light yellow precursor powder. Put the precursor powder in a crucible, place it in a vacuum sintering furnace, raise the temperature at a rate of 2°C / min under a vacuum of 10Pa, pre-decompose at 320°C for 4 hours, raise the temperature to 650°C at the same rate, and calcine After 15 hours, t...

Embodiment 2

[0055] 1. LiFePO 4 / C and Li 4 Ti 5 o 12 Preparation of / C

[0056] Same as Example 1

[0057] 2. Preparation of power lithium-ion battery

[0058] The preparation of the positive and negative electrodes and the assembly process of the battery are the same as in Example 1, the difference is that the LiFePO in the positive electrode mixed powder 4 The proportions of / C, Super P and PVDF are: 85%, 7%, 8% respectively; Li in the negative electrode mixed powder 4 Ti 5 o 12 The proportions of / C, Super P, SBR and CMC are: 85%, 3%, 8%, 4%, respectively.

[0059] Under the discharge rate of 0.1C, the specific capacity of the battery prepared in this example reached 158mAh for the first time, and the discharge platform was stable between 1.80 and 1.90; under the discharge rate of 1C, the specific capacity remained above 115mAh / g after 3000 cycles; The high-rate performance is good, and the specific capacity is above 120mAh for the first time under the discharge rate of 10C. ...

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Abstract

The invention relates to a lithium ion battery, more particularly to a power lithium ion battery. The inventive power lithium ion battery comprises an anode, a cathode, and a membrane between the anode and the cathode and organic electrolyte, wherein, the active material of the anode is nanometer LiFePO4/C which accounts for 85-95% (by mass) of the mixed powders of the anode; the active material of the cathode is nanometer Li4Ti5O12/C which accounts for 85-95% (by mass) of the mixed powders of the cathode; the organic electrolyte takes LiPF6 as an electrolyte and takes EC and DEC as solvents. Compared with the existing lithium ion battery which serves as the power source of electric vehicle, the inventive power lithium ion battery is good in conductivity, high in safety, stable in discharging, long in cycle life and excellent in high-current charging and discharging; the invention is extremely suitable for the power source of the electric vehicle.

Description

Technical field: [0001] The invention relates to a lithium ion battery, in particular to a power lithium ion battery. Background technique: [0002] In the 21st century, oil resources are becoming increasingly scarce and environmental pollution is becoming more and more serious. People are paying more and more attention to secondary energy powered by green secondary batteries. With the progress of society and science, the use of lithium-ion batteries as the power source of electric vehicles has become a hot spot in the high-tech industry. [0003] Lithium-ion batteries that are currently being studied are: [0004] 1. With LiCoO 2 The commercial lithium-ion battery is a positive electrode and graphite is a negative electrode, but due to the strong oxidative Co + , it is easy to cause the electrolyte to decompose, leading to the explosion of the battery, the safety performance is poor, and it cannot be used as a power source for electric vehicles. [0005] 2. With LiMn 2...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/40H01M4/36H01M4/58H01M4/38H01M4/48
CPCY02E60/12Y02E60/10
Inventor 李庆余李泽胜王红强张初华王艳芳陈美超胡思江王芳平
Owner GUILIN JIUYI NEW ENERGY SCI & TECH CORP
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