Negative plate and lithium ion battery comprising same

A negative electrode and negative electrode technology, applied in the direction of negative electrodes, battery electrodes, secondary batteries, etc., can solve the problems of insufficient battery cycle life, low porosity of the electrode sheet, and limited ability to improve battery performance.

Pending Publication Date: 2020-11-06
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the main ways to increase the energy density of the battery are: 1. Increase the compaction density of the positive and negative electrode materials, but the high pressure will lead to low porosity of the pole piece, and the subsequent reduction of the liquid retention capacity, which will lead to insufficient cycle life of the battery; 2. Increase the gram capacity of negative electrode materials, that is, use silicon-based negative electrode materials to replace graphite, but the large volume change of silicon-based materials during charge and discharge will cause the material to be pulverized

Method used

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  • Negative plate and lithium ion battery comprising same
  • Negative plate and lithium ion battery comprising same
  • Negative plate and lithium ion battery comprising same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0092] (1) Preparation of positive electrode sheet:

[0093] The cathode active material LiCoO 2 , the binder PVDF, and the conductive agent Super P are dissolved in N-methylpyrrolidone (NMP) according to the mass ratio of 97%: 1.5%: 1.5%, and stirred evenly to make a slurry, and evenly coated on both sides of the aluminum foil of the positive electrode current collector On the surface, it is baked at 100-150°C for 4-8 hours, and then cold-pressed and cut to make positive electrodes for lithium-ion batteries, with a compacted density of 4.1g / cm 3 , the thickness of the positive electrode active material layer on one side is 62 μm.

[0094] (2) Preparation of negative electrode conductive paste:

[0095] Super P and PVDF were mixed and dissolved in NMP at a mass ratio of 97:3 to obtain a conductive coating paste with a solid content of 45%.

[0096] (3) Preparation of negative electrode first negative electrode slurry:

[0097]Artificial graphite, conductive agent SP, SBR a...

Embodiment 2

[0110] The difference between this embodiment and Example 1 is: replace Super P in the conductive coating with carbon nanotubes, replace acetylene black in the buffer coating with Ketjen Black, and use zirconium nitride ceramics (D 90 ≤2μm) to replace alumina ceramics in safety coatings.

Embodiment 3

[0112] The difference between this example and Example 1 is that the thickness of the coating layer on the surface of the negative electrode current collector is different, as shown in Table 1; the compacted density of the negative electrode sheet is 1.55g / cm 3 ; Due to the change of the pressure density of the negative electrode sheet, adjust the thickness of the positive electrode active material layer on one side of the positive electrode sheet to 22 μm.

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Abstract

The invention provides a negative plate and a lithium ion battery comprising the same. The negative plate is formed by coating a conductive coating between a negative current collector and a first negative active material layer, so that the contact resistance between the first negative electrode active material layer and the negative electrode current collector can be reduced, the acting force between the first negative electrode active material layer and the negative electrode current collector is improved, peeling of the first negative electrode active material layer is avoided, the buffer coating is coated between the first negative electrode active material layer and the second negative electrode active material layer, the contact resistance between the first negative electrode activematerial layer and the second negative electrode active material layer can be reduced, the acting force between the first negative electrode active material layer and the second negative electrode active material layer is improved, and the transmission rate of ions and electrons is increased; and the surface of the second negative electrode active material layer is coated with the safety coating,so that the volume expansion of the second negative electrode active material layer is further buffered, the lithium dendrites can be prevented from directly piercing the diaphragm to cause internal short circuit, and the safety risk is reduced.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative electrode sheet and a lithium ion battery including the negative electrode sheet. Background technique [0002] In recent years, with the continuous expansion of lithium-ion battery industrialization and the continuous development of technology, people's requirements for lithium-ion batteries have gradually increased, and lithium-ion batteries with high energy density, long cycle life and high safety have become the research and development focus. At present, the main ways to increase the energy density of the battery are: 1. Increase the compaction density of the positive and negative electrode materials, but the high pressure will lead to low porosity of the pole piece, and the subsequent reduction of the liquid retention capacity, which will lead to insufficient cycle life of the battery; 2. Increase the gram capacity of negative electrode...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/04H01M4/583H01M4/62H01M10/0525H01M4/02
CPCH01M4/0404H01M4/366H01M4/583H01M4/622H01M4/625H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 欧长志彭冲李俊义徐延铭
Owner ZHUHAI COSMX BATTERY CO LTD
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