Lithium ion battery, positive electrode sheet thereof and preparation method thereof

A lithium-ion battery and positive electrode technology, which is applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as great processing safety, damage to electrolyte system, and impact on battery performance.

Inactive Publication Date: 2019-05-07
江西星盈科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The inventors found in the process of carrying out the research of the present invention that no matter lithium metal or lithium powder has low potential and high chemical reactivity, it is easy to burn in the air, and there is a big problem of processing safety, and it is different from the existing There are compatibility issues with solvents and binders, for example, stabilized lithium metal powder (SLMP) will react with NMP, a commonly used slurrying solvent, and cause explosion hazards
[0007] In addition, in the prior art, the battery is designed with a built-in lithium metal sheet and made into three electrodes to supplement lithium to the system, such as CN201310336418.5 and CN201310463949.0. Lithium metal is easily oxidized and burns when exposed to the air, so this This method also has a great processing safety problem, and the reactivity of lithium metal with the electrolyte is high. Since the lithium element will react with the electrolyte, it is easy to cause damage to the electrolyte system and ultimately affect the performance of the entire battery.

Method used

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  • Lithium ion battery, positive electrode sheet thereof and preparation method thereof
  • Lithium ion battery, positive electrode sheet thereof and preparation method thereof

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Experimental program
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preparation example Construction

[0155] The preparation process of the positive electrode sheet of the present embodiment is as follows:

[0156] 1) Preparation of lithium supplement material layer slurry: add lithium-containing compound, transition metal, conductive agent and PVDF into the ball mill tank according to the predetermined ratio above, add a certain volume of NMP solvent, and then use nitrogen or argon as an inert gas under the protection , or lower than -95Kp environment, perform high-speed ball milling, and separate the slurry after ball milling.

[0157] 2) Coating the slurry onto the current collector using a gravure roller, and drying to obtain a current collector coated with a lithium-replenishing material layer.

[0158] 3) Preparation of positive electrode sheet: add a certain amount of NMP solvent according to the mixture of positive electrode active material, conductive agent and binder in the predetermined ratio above, and disperse and stir evenly at high speed, and transfer or extrude...

experiment example 11

[0170] 1. Preparation of positive electrode sheet

[0171] 1.1 Preparation of lithium-supplementing material layer

[0172] Will Li 2 S powder, Co powder, conductive carbon black (SP) and polyvinylidene fluoride (PVDF) were dispersed in N-methylpyrrolidone, and the slurry was formed by high-energy ball milling under nitrogen atmosphere for 12 h.

[0173] Among them, Li 2 The mass ratio of S:Co:SP:PVDF is: 58:37:2.5:2.5;

[0174] Coat the lithium-supplementing slurry on both sides of the aluminum foil (thickness 12 μm), and then dry at 90°C for 10 minutes to form a lithium-supplementing material layer on both sides of the aluminum foil. After drying, the coated surface density is 0.26 mg / cm2.

[0175] 1.2 Formation of positive electrode active material layer

[0176] Lithium cobaltate, conductive carbon black and polyvinylidene fluoride are dispersed in N-methylpyrrolidone to form positive electrode active material slurry. Wherein, the weight ratio of lithium cobaltate: co...

experiment example 12

[0182] Compared with Experimental Example 11, the only difference is that Li in this Experimental Example 12 2 The mass ratio of S: Co: SP: PVDF is: where, Li 2 The mass ratio of S:Co:SP:PVDF is: 59:38:1.5:1.5

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Abstract

The invention relates to the field of lithium ion batteries and discloses a lithium ion battery, a positive electrode sheet thereof and a preparation method thereof. The positive electrode sheet includes: a current collector coated with a positive electrode active material layer and a lithium-replenishing material layer, wherein the positive electrode active material layer is coated with a mixtureof a positive electrode active material, a conductive agent, and a binder; the lithium-replenishing material layer is coated with a mixture of Li2S, transition metal, a conductive agent, and a binder. The application of the technical solution improves the reversible gram capacity of the lithium ion battery on the basis of ensuring the safety of the production and use of the lithium ion battery.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, and discloses a lithium ion battery, a positive electrode sheet and a preparation method thereof. Background technique [0002] The gradual depletion of fossil energy and the increasing severity of the greenhouse effect have prompted researchers to explore sustainable and clean energy. Since Sony first commercialized lithium-ion batteries in 1991, lithium-ion batteries have been widely used in 3C digital products. Since lithium-ion batteries have advantages over traditional lead-acid batteries in terms of cycle life, volumetric energy density, and mass energy density, many technicians have been working on the commercialization of lithium-ion batteries as power batteries in the past 20 years. [0003] The actual available energy density and cycle life of the full battery are closely related to the first coulombic efficiency of the lithium-ion battery and the formation of the negative electrod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/136H01M4/1397H01M4/36H01M4/58H01M10/0525
CPCY02E60/10
Inventor 郭永兴卢林李成浩高旭光
Owner 江西星盈科技有限公司
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