Lithium ion secondary battery and diaphragm thereof

A technology for secondary batteries and separators, applied in secondary batteries, battery pack components, circuits, etc., can solve the problems of low ionic conductivity, affecting the cycle performance of lithium ion secondary batteries, rate performance, and poor electrolyte affinity.

Active Publication Date: 2014-07-23
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main problems of polyolefin as a separator are poor electrolyte affinity and low ion conductivity, which seriously affect the cycle performance and rate performance of lithium-ion secondary batteries.

Method used

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  • Lithium ion secondary battery and diaphragm thereof
  • Lithium ion secondary battery and diaphragm thereof
  • Lithium ion secondary battery and diaphragm thereof

Examples

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preparation example Construction

[0034] The first preparation method of the separator of the lithium ion secondary battery according to the second aspect of the present invention is used to prepare the separator with the structure of formula 1, comprising the steps of: (1) high-energy irradiation: the polymer substrate is irradiated Carry out high-energy irradiation indoors to generate free radicals to obtain polymer substrates with free radicals; (2) first grafting: immerse the polymer substrates with free radicals in a solution containing monomer B for The first grafting reaction to obtain the polymer base material after the first grafting; (3) the second grafting: the polymer base material after the first grafting is immersed in the solution containing halogenated hydrocarbon Carrying out the second grafting reaction to obtain the polymer base material after the second grafting; (4) drying: drying the obtained polymer base material to obtain a separator, which has a structure of formula 1;

[0035]

[0...

Embodiment 1

[0109] Preparation of separator for lithium-ion secondary battery

[0110] (1) Remove the surface impurities of the polymer base polyethylene film and put it in 60 Irradiate in Co gamma ray irradiation room, and the irradiation dose is 65KGy to obtain polyethylene film with free radicals;

[0111] (2) Immerse the polyethylene film with free radicals in the N,N-dimethylformamide solution with a mass fraction of 50% vinylpyridine (monomer B), and after deoxygenation by nitrogen, at 60 ° C React 12h under constant temperature water bath, obtain the polyethylene film after grafting for the first time, by weighing the quality of polyethylene film before and after grafting and take the quality of polyethylene film as 100%, the grafting rate of calculation is 5.10%;

[0112] (3) Immerse the polyethylene film after the first grafting in the N,N-dimethylformamide solution with a mass fraction of 37% benzyl bromide (halogenated hydrocarbon), and react in a constant temperature water bath...

Embodiment 2

[0124] Lithium-ion secondary batteries were prepared according to the method of Example 1, the difference being:

[0125] Preparation of separator for lithium-ion secondary battery

[0126] (1) The polymer substrate is polypropylene film, and the irradiation dose is 76KGy;

[0127] (2) Monomer B is vinylthiophene, the solvent that adopts is N-methylpyrrolidone (NMP), the mass fraction of monomer B is 65%, the temperature of constant temperature water bath is 80 ℃, and reaction time is 23h, grafting rate 5.90%;

[0128] (3) Halogenated hydrocarbon is biphenyl dichlorobenzyl, the solvent that adopts is N-methylpyrrolidone (NMP), the mass fraction of halogenated hydrocarbon is 35%, the temperature of constant temperature water bath is 100 ℃, and the reaction time is 20h, then Branch rate is 5.71%;

[0129] (4) Lithium salt is LiAsF 6 , the solvent used is ethylene carbonate, the mass fraction of lithium salt is 10%, the temperature of the constant temperature water bath is 45...

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Abstract

The invention provides a lithium ion secondary battery and a diaphragm thereof. The diaphragm of the lithium ion secondary battery comprises a polymer base material, wherein the surface of the polymer base material contains a compound with an onium salt structure. The lithium ion secondary battery comprises a positive electrode plate, a negative electrode plate, the diaphragm for isolating the positive electrode plate from the negative electrode plate, and electrolyte, wherein the diaphragm is a diaphragm of the lithium ion secondary battery. The diaphragm has the high ionic conductivity and the high electrolyte absorption volume; the lithium ion secondary battery has the good rate capability and the good normal-temperature cycling performance.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery and a separator thereof. Background technique [0002] Lithium-ion secondary batteries are currently widely used in mobile phones, notebooks, tablet computers, electric vehicles and other fields. Compared with lead-acid batteries and nickel-metal hydride batteries, lithium-ion secondary batteries have the advantages of environmental friendliness, high energy density, long cycle life, and high voltage. Generally, lithium-ion secondary batteries are composed of a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. Among them, the separator connects and separates the positive and negative plates, allowing ions to pass through and isolating electrons. Therefore, the performance of the separator determines the interface structure and internal resistance of the lithium-ion secondary battery, which in turn affects th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M10/0525H01M50/414H01M50/497
CPCH01M10/0525H01M50/411Y02E60/10
Inventor 伍永彬程晟牛少军申红光何东铭
Owner NINGDE AMPEREX TECH
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