A flexible lithium-ion battery electrode sheet using a backing layer and its preparation method

A lithium-ion battery and electrode sheet technology, which is applied in the field of electrochemistry, can solve the problems of inflexibility, bulkiness, and high self-discharge rate, and achieve the effect of strengthening mechanical strength and flexibility, not polluting the environment, and improving flexibility

Active Publication Date: 2021-03-02
柔电(武汉)科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In existing lithium-ion batteries, current collectors usually use metal sheets, such as copper foil and aluminum foil. However, these metal sheets generally cannot be bent and squeezed, and are not flexible. Therefore, lithium-ion batteries have considerable hardness and cannot Accepts deformation due to external force
If the lithium-ion battery is deformed, it will damage the interface between the positive and negative plates and the diaphragm, resulting in deterioration of battery performance and affecting the normal use of end users
At the same time, the existing lithium-ion batteries usually contain electrolyte, and the self-discharge rate is high, which is easy to cause liquid leakage, and the safety needs to be further improved
[0003] With the rapid development of electronic technology, more and more electronic devices are developing towards thinner and more flexible. For example, Samsung and LG have launched their own flexible and foldable screens, and are planning to launch foldable mobile phones. Currently, display components and circuits can be flexible and foldable. The biggest challenge at present is the energy storage power products that can be folded. Traditional lithium-ion batteries, super capacitors and other products are not only bulky, but also cannot be folded. When the volume change is too large, it may even lead to a short circuit between the positive and negative electrodes, causing thermal runaway and causing serious safety problems

Method used

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  • A flexible lithium-ion battery electrode sheet using a backing layer and its preparation method
  • A flexible lithium-ion battery electrode sheet using a backing layer and its preparation method
  • A flexible lithium-ion battery electrode sheet using a backing layer and its preparation method

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preparation example Construction

[0034] In the present invention, the preparation method of the flexible lithium-ion battery electrode sheet using the cushion layer includes: dispersing, stirring, preparation of cushion layer suspension, filtering, baking and rolling, and the specific implementation method is:

[0035] (1) Dispersion: use an organic solvent or deionized water as a solvent for the conductive agent, and ultrasonically disperse it at a dispersion concentration of 0.1 to 2 mg / ml to form a conductive agent slurry; use an organic solvent or deionized water as a solvent for the matrix , high-speed stirring dispersion, dispersion concentration of 0.5 ~ 3mg / ml.

[0036](2) Stirring: Add binder to the conductive agent slurry in step (1) to disperse for 2 to 3 minutes, then add the active material, mix thoroughly, then add the matrix dispersed in step (1), fully Stir to mix well to form a suspension slurry.

[0037] (3) Cushion suspension preparation: add nanocellulose to organic solvent or deionized w...

Embodiment 1

[0043] Take carbon nanotubes with a mass fraction of 5% and add them to isopropanol and sonicate for 20 minutes to prepare a conductive agent slurry; disperse lithium cobalt oxide particles with a mass fraction of 89% in the conductive agent slurry, stir at high speed for 5 minutes, and cobalt acid The surface density of lithium particles is 38mg / cm 2 Prepare a mixed solution of conductive agent and active material; then take nanocellulose with a mass fraction of 5% as a matrix and add isopropanol and stir at high speed for 5 minutes to form a base liquid, and mix the base liquid with the prepared mixed solution of conductive agent and active material Mix and stir at high speed for 5 minutes to prepare a suspension slurry; then take nanocellulose with a mass fraction of 1% as a cushion and disperse with isopropanol at high speed for 3 minutes, and the surface density is 1mg / cm 2 Prepare a cushion suspension; pour the cushion suspension into cellulose filter paper with a pore s...

Embodiment 2

[0048] Add carbon nanotubes with a mass fraction of 6% to isopropanol and sonicate for 15 minutes to prepare a conductive agent slurry; disperse graphite particles with a mass fraction of 83% in the conductive agent slurry, stir at high speed for 6 minutes, and press the graphite particles on the surface Density 25mg / cm 2 Prepare a mixed solution of conductive agent and active material; take nanocellulose with a mass fraction of 8% as a matrix, add isopropanol and stir at high speed for 8 minutes to form a base liquid, and mix the base liquid with the prepared mixed solution of conductive agent and active material , stirred at a high speed for 8 minutes, and prepared into a suspension slurry; the mass fraction was 3% nanocellulose and isopropanol were dispersed at a high speed for 5 minutes, and the surface density was 0.8 mg / cm 2 Prepare a cushion suspension; pour the cushion suspension into cellulose filter paper with a pore size of 70 microns for vacuum filtration, and when...

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Abstract

The invention provides a flexible lithium-ion battery electrode sheet using a cushion layer, including a cushion layer, a matrix, an active material and a conductive agent arranged on the cushion layer, the cushion layer is nanocellulose, and the matrix is ​​nanometer cellulose. The fiber or multi-dendritic fiber has a fiber body diameter of nanometer or submicron; the active material and conductive agent are dispersed in the matrix, and the active material is a positive electrode material or a negative electrode material of a lithium ion battery. The battery prepared by the electrode sheet not only has the charging and discharging function of the traditional lithium battery, but also the electrode sheet of the flexible lithium ion battery itself makes the active material evenly dispersed in it through the self-supporting effect of the matrix, and has a certain degree of flexibility. Among them, the slurry loss rate can be reduced by the cushion layer, so that the loss rate can be basically zero.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a flexible lithium-ion battery electrode sheet using a backing layer and a preparation method thereof. Background technique [0002] Lithium-ion battery is a secondary battery with high energy density, high reliability, good processability and excellent environmental performance, and has been widely used in various portable electronic devices. Existing lithium-ion batteries include positive pole pieces, separators, negative pole pieces and electrolyte that are superimposed and wound on each other, and the separator is spaced between adjacent positive and negative pole pieces to insulate the positive and negative pole pieces and is used to maintain the electrolyte; The positive electrode sheet includes a positive electrode current collector and a positive electrode material layer formed on the surface of the positive electrode current collector; the negative e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/131H01M4/133H01M4/139H01M4/1391H01M4/1393H01M4/04H01M10/0525
CPCY02E60/10
Inventor 熊红波胡韬解明
Owner 柔电(武汉)科技有限公司
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