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Pole piece and lithium ion battery thereof

A pole piece and resistor technology, applied in the field of pole pieces and lithium-ion batteries, can solve the problems of low cycle performance and life, capacity attenuation, poor activity, etc., and achieve the effect of improving cycle life, safety performance, and safety performance

Active Publication Date: 2018-12-25
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, for the electrode pole piece of the multilayer structure (such as figure 1 As shown), the inner layer 20 usually adopts the positive electrode material with poor activity and high stability, and the outer layer 30 usually adopts the positive electrode material with better activity. The lithium ion battery made of this electrode structure, although it is pierced, extruded, The pass rate of performance safety testing such as impact is significantly higher than that of lithium-ion batteries with a single-layer electrode structure, which improves the safety performance of lithium-ion batteries; however, due to the poor activity of the positive electrode material in the inner layer, the lithium-ion battery will , its cycle performance deteriorates, its capacity fades seriously, and its cycle performance and life are significantly lower than those of lithium-ion batteries with a single-layer electrode structure

Method used

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  • Pole piece and lithium ion battery thereof
  • Pole piece and lithium ion battery thereof
  • Pole piece and lithium ion battery thereof

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Experimental program
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Effect test

preparation example Construction

[0060] The preparation of the positive electrode sheet 400 will be specifically described below, so as to better understand the present invention.

[0061] The positive pole piece 400 uses aluminum foil as the current collector 401;

[0062] The first active material of the first coating 402a adopts some common positive electrode active materials, such as one or more of lithium cobaltate, lithium iron phosphate, nickel-cobalt-manganese ternary material, and lithium titanate; Some common binders, such as polyethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polypropylene methyl methacrylate, polyacrylonitrile, polyethylene oxide, polypropylene oxide One or more; the conductive agent adopts some common conductive agents, such as one or more of conductive carbon black, carbon nanotubes, acetylene black, conductive graphite, and graphene; the solvent adopts some common solvents, such as using One or more of ethanol, acetone, butanone, dimethylformami...

Embodiment 1

[0072] The first coating 402a of the positive electrode is incompletely coated and has a plurality of through holes 402b:

[0073] The positive pole piece 400 uses aluminum foil as the current collector 401;

[0074] The positive first coating 402a uses lithium iron phosphate as the main active material, conductive carbon black as the conductive agent, vinylidene fluoride as the binder, and N-methylpyrrolidone as the dispersant. The positive first coating 402a The mass composition of the material is 96.5% lithium iron phosphate, 1% conductive carbon black, and 2.5% polyvinylidene fluoride; firstly, the active material, conductive agent and binder are mixed uniformly in a mixer, and then N-methylpyrrolidone is added to The above powder is dispersed, and then N-methylpyrrolidone pre-dissolved polyvinylidene fluoride solution is added and stirred evenly to obtain a slurry.

[0075] Use a gravure roll with local pocket-free regions 40 (such as Figure 8 As shown) coating one of ...

Embodiment 2

[0082] Same as Embodiment 1, except that the cross-sectional area of ​​the through hole 402b is 5% of the cross-sectional area of ​​the first coating 402a.

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Abstract

The invention provides a pole piece and a lithium ion battery thereof. The pole piece comprises: a current collector, a first coating layer coated with a first active material on at least one surfaceof the current collector; Wherein the first coating comprises at least one through-hole, the cross-sectional area of the at least one through-hole being 1% to 20% of the cross-sectional area of the first coating. The present invention forms a first coating layer comprising at least one through hole on at least one surface of the current collector, and a second coating layer is provided on the first coating layer, the second coating layer can be connected with the current collector through the through hole, and the activity of the first coating layer is less than that of the second coating layer. Compared with the lithium ion battery with single layer electrode structure (only the second coating), the safety performance of the lithium ion battery with the electrode plate can be improved, and the cycle life of the lithium ion battery with the first coating layer electrode plate without through hole is obviously improved.

Description

technical field [0001] The present application relates to the technical field of batteries, and more specifically, to a pole piece and a lithium-ion battery thereof. Background technique [0002] With the rapid development of science and technology, lithium-ion batteries have been widely used in various fields of life, and their safety issues have been paid more and more attention. Lithium-ion battery safety accidents are mainly caused by high current and high temperature generated by internal or external short-circuit of lithium-ion batteries, which can cause combustion, explosion or other safety problems. [0003] In the internal short circuit of lithium-ion batteries, the risk of short circuit thermal runaway of the positive electrode current collector and the negative electrode active material layer is the greatest. Generally, the following methods are used to reduce the short circuit risk: 1) reduce the possibility of short circuit between the positive electrode curren...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/04H01M4/36H01M10/0525H01M10/058H01M50/586
CPCH01M4/0404H01M4/13H01M4/366H01M10/0525H01M10/058H01M50/586H01M2004/021H01M10/4235H01M2004/028Y02E60/10Y02P70/50H01M4/78H01M2004/025
Inventor 雷廷玲戴志芳陶兴华龙海
Owner NINGDE AMPEREX TECH