Negative electrode, lithium ion secondary battery and preparation method of lithium ion secondary battery

A secondary battery, lithium ion technology, used in secondary batteries, negative electrodes, battery electrodes, etc.

Inactive Publication Date: 2021-02-23
MICROVAST POWER SYST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a negative electrode, a lithium ion secondary battery and a preparation method thereof. Through the charging process, the excess lithium ions of the positive electrode are precipitated and deposited in the pores of the negative electrode, so that th

Method used

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  • Negative electrode, lithium ion secondary battery and preparation method of lithium ion secondary battery
  • Negative electrode, lithium ion secondary battery and preparation method of lithium ion secondary battery
  • Negative electrode, lithium ion secondary battery and preparation method of lithium ion secondary battery

Examples

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Example Embodiment

[0053]This embodiment also provides a method of preparing a lithium ion secondary battery as described above, comprising the steps:

[0054]The first negative electrode active material, the conductive agent, the binder, the pore bracket material, and the solvent are mixed into an negative electrode mixture, and the negative electrode mixture is applied to the negative electrode fluid to form a negative electrode sheet; wherein the aperture bracket material is constituted. The electrically conductive network structure of the negative electrode sheet.

[0055]The positive electrode active material, the conductive agent, the adhesive, and the solvent are uniformly prepared, and the positive electrode mixture is applied to the positive electrode concentration fluid to form a positive electrode sheet;

[0056]The positive electrode sheet, the negative electrode, the diaphragm, and the electrolytic solution are assembled into the battery;

[0057]The battery is charged to the upper limit voltage, and...

Example

[0061][First Embodiment]

[0062]35 wt% MCMB (intermediate carbon microspheres), 10% by weight of conductive carbon black, 30 wt% conductive carbon fiber, 25 wt% PVDF (polyvinylidene fluoride) with a moderate amount of NMP (N-methylpyrrolidone) stirred homogenate The negative electrode material layer, wherein the MCMB is used as a first negative active material, conductive carbon black as a conductive agent, a conductive carbon fiber as a pore bracket material, a PVDF as an adhesive, NMP as a solvent.

[0063]Then, the negative electrode material layer is coated on the negative electrode fluid (surface density 160 g / cm)2Based on the oven; then the roll compaction is carried out, the compaction density is 0.8 g / cc; the negative electrode sheet that meets the dimensional requirements is obtained by croping.

[0064]Figure 2a A structural diagram of a conductive network structure under an electrical microscope is a structural diagram of a conductive network structure in a first embodiment o...

Example

[0065][Second Embodiment]

[0066]35 wt.% McMB (intermediate carbon microspheres), 10 wt.% Conductive carbon black, 30 wt.% Conductive carbon fiber, 25 wt.% PVDF (polyvinylidene fluoride) is stirred with an appropriate amount of NMP (N-methylpyrrolidone) Homochrome is made into a mixture; coating the mixture on the negative electrode fluid (surface density 160g / cm)2Between the oven; then the roll pressure is carried out, the compaction density is 0.96 g / cc; the negative electrode that meets the size required by croping.

[0067]Figure 2b A structural diagram of a conductive network structure in an electrical microscope is a second embodiment of the present invention. Please combineFigure 2b The same has a continuous and large amount of conductive holes in the figure, that is, the second embodiment of the present invention also constitutes a negative structure that can be deposited in the conductive network structure 20 in the conductive network structure 20. Further, since the compact...

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Abstract

The invention provides a negative electrode. The negative electrode comprises a first negative electrode active material, a conductive network structure with holes and a second negative electrode active material positioned in the holes, the second negative electrode active material is lithium metal, and the lithium metal is deposited in the conductive network structure and is not separated out from the surface of the negative electrode. The invention further provides a lithium ion secondary battery comprising the negative electrode and a preparation method of the lithium ion secondary battery,excessive lithium ions of the positive electrode are separated out and deposited in holes of the negative electrode through a charging process, so that lithium metal and a negative electrode active material jointly form the negative electrode, and the problem of lithium separation on the surface of the negative electrode in a battery circulation process is solved; the formation of lithium dendrites is avoided, so that the safety of the battery is improved; meanwhile, the negative electrode has two charging and discharging forms of lithium metal and graphite with different mechanisms, so thatthe energy density and the cycle performance of the battery are improved.

Description

technical field [0001] The invention relates to a negative electrode for a lithium secondary battery, a lithium secondary battery containing the negative electrode and a preparation method thereof. Background technique [0002] In the past 20 years, lithium-ion batteries, as a new energy industry, have shown rapid development. With the development of lithium battery technology, the performance of lithium ion batteries has become more and more diversified, and gradually entered various fields of production and life. In the field of new energy vehicles, in order to achieve higher mileage, lithium-ion secondary batteries as power sources are required to have higher and higher energy densities. To this end, researchers are working on developing new high-voltage or high-capacity electrode materials. In terms of positive electrodes, the method of increasing the Ni content in ternary materials (NCM, NCA) is usually used to achieve the purpose of increasing the energy density of l...

Claims

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Application Information

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IPC IPC(8): H01M4/134H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/134H01M4/362H01M4/382H01M4/583H01M4/625H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 孟嘉锋刘文娟王晓亚陈方平高丽君李思昊
Owner MICROVAST POWER SYST CO LTD
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