Negative pole piece as well as preparation method and application thereof

A technology of negative electrode sheet and electrode layer, applied in the field of negative electrode sheet and its preparation, can solve the problems of reducing battery power performance, affecting battery cycle performance, and high cost of PTC coating, so as to improve thermal stability and electrochemical performance Effect

Pending Publication Date: 2022-03-01
HUBEI JINQUAN NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the poor conductivity of the PTC coating itself, the power performance of the battery will deteriorate, and the cost of the PTC coating is high
Another example is to coat the surface of the positive electrode with alkaline oxide (aluminum oxide, etc.) to improve safety performance, but since the oxide has no capacity, the energy density of the battery will be reduced, and the power performance of the battery will also be reduced
[0004] CN201466143U discloses a kind of lithium-ion battery that can improve PTC protection efficiency, fuse PTC is connected between battery cell negative pole and protective plate, external PTC design can only prevent overcharging, but not sensitive enough to temperature sensing, when battery internal temperature produces , unable to sense instantly for protection
In the above-mentioned patents, the gram capacity, rate performance and voltage platform performance of the negative electrode material have all been improved, but due to the high activity of the outer coating material and the direct contact with the electrolyte in the battery, the compatibility between the material and the electrolyte is poor. And then affect the cycle performance of the battery

Method used

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  • Negative pole piece as well as preparation method and application thereof
  • Negative pole piece as well as preparation method and application thereof
  • Negative pole piece as well as preparation method and application thereof

Examples

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Embodiment 1

[0049] This embodiment provides a negative electrode sheet, which includes a current collector 1, an electrode layer 2, and a safety coating 3 that are sequentially stacked; the safety coating 3 includes lithium titanate, aluminum oxide, carbon black and polyvinylidene fluoride;

[0050] Wherein, the thickness of the security coating 3 is 3 μm, the median particle size of lithium titanate is 1 μm, and the median particle size of aluminum oxide is 350 nm;

[0051] In the safety coating 3, the mass proportion of lithium titanate is 77%, the mass proportion of aluminum oxide is 15%, the mass proportion of carbon black is 5%, and the mass proportion of polyvinylidene fluoride is 3%. .

[0052] The preparation method of the negative electrode sheet is as follows:

[0053] Mix artificial graphite, conductive carbon black (SP), styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) in a mass ratio of 95:1:2.5:1.5, add deionized water, and prepare negative electrode...

Embodiment 2

[0056] This embodiment provides a negative electrode sheet, which includes a current collector, an electrode layer, and a safety coating layered in sequence; the safety coating includes lithium titanate, boehmite, carbon nanotubes, and polyacrylic acid ;

[0057] Among them, the thickness of the safety coating is 5 μm, the median particle size of lithium titanate is 2 μm, and the median particle size of aluminum oxide is 580 nm;

[0058] In the safety coating, the mass proportion of lithium titanate is 80%, the mass proportion of boehmite is 12%, the mass proportion of carbon black is 3%, and the mass proportion of polyacrylic acid is 5%.

[0059] The preparation method of the negative electrode sheet is as follows:

[0060] Mix natural graphite, conductive carbon black (SP), styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) in a mass ratio of 95:1.5:2:1.5, add deionized water, and prepare negative electrode slurry The negative electrode slurry is coate...

Embodiment 3

[0063] This embodiment provides a negative electrode sheet, which includes a current collector, an electrode layer, and a safety coating layered in sequence; the safety coating includes lithium titanate, aluminum oxide, carbon black, and polybias vinyl fluoride;

[0064] Among them, the thickness of the safety coating is 2 μm, the median particle size of lithium titanate is 0.5 μm, and the median particle size of aluminum oxide is 100 nm;

[0065] In the safety coating, the mass proportion of lithium titanate is 72%, the mass proportion of aluminum oxide is 20%, the mass proportion of carbon black is 4%, and the mass proportion of polyvinylidene fluoride is 4%.

[0066] The preparation method of the negative electrode sheet is as follows:

[0067] Artificial graphite, conductive carbon black (SP), and polyacrylic acid are mixed in a mass ratio of 97:1:2, and deionized water is added to prepare negative electrode slurry, and the negative electrode slurry is coated on both side...

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Abstract

The invention provides a negative pole piece as well as a preparation method and application thereof. The negative pole piece comprises a current collector, an electrode layer and a safety coating which are sequentially stacked; the safety coating comprises lithium titanate, a conductive agent and a binder. The safe coating is arranged on the surface of the electrode layer of the negative electrode plate, and lithium titanate can be used as a safe material and an active substance at the same time through the synergistic effect of lithium titanate and the conductive agent, so that the thermal stability of the negative electrode plate of the lithium ion battery is improved, and other electrochemical properties such as rate capability and cycle performance are also improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a negative pole piece, a preparation method and application thereof. Background technique [0002] As a green and environmentally friendly new energy, lithium-ion batteries have the advantages of good reliability, high safety, small size, and light weight. At present, they have been widely used in digital products, electric vehicles, military products and other fields. The development of lithium-ion batteries is in full swing, but the requirements for the service life, safety and low cost of lithium-ion batteries are also getting higher and higher. At present, lithium-ion batteries are also developing in the direction of long life, high safety, high rate and low cost. [0003] Safety performance is the key issue of lithium-ion batteries. The current methods to solve the safety of lithium-ion batteries mainly focus on the improvement of positive electrode coating. For...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/485H01M4/62H01M4/139H01M10/0525H01M10/42
CPCH01M4/13H01M4/485H01M4/62H01M4/139H01M10/0525H01M10/4235H01M2004/021H01M2004/027Y02E60/10
Inventor 陈校军江紫翔程泽鸿袁超平宋鹏元
Owner HUBEI JINQUAN NEW MATERIALS CO LTD
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