Negative electrode piece, preparation method thereof and lithium ion battery

A technology for lithium-ion batteries and negative pole pieces, which is applied in the direction of negative electrodes, electrode manufacturing, and secondary batteries. It can solve problems such as large polarization, attenuation of lithium analysis capacity, and capacity limitations of lithium cobalt oxide materials, so as to reduce polarization. , Improve the overpotential, improve the effect of lithium precipitation and capacity retention

Pending Publication Date: 2022-02-01
东莞维科电池有限公司
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Problems solved by technology

[0002]Lithium cobalt oxide material has the advantages of high voltage and high compaction density as the positive electrode material of lithium ion battery, and is an ideal positive electrode material for lithium ion battery, but in conventional 4.2 At a charging voltage of around V, the capacity of lithium cobalt oxide materials is limited, and increasing the charging voltage of lithium cobalt oxide batteries can increase the volumetric energy density of the battery
Therefore, the research on lithium-ion batteries is now turned to high-voltage (charging voltage ≥ 4.45V) lithium cobalt oxide as the positive electrode material of lithium-ion batteries, which can increase the volumetric energy density of the battery, but the polarization is large during the cycle, and it is prone to precipitation. Lithium and fast capacity fading and other problems are currently mainly solved by improving the kinetic properties of the negative electrode, but they cannot be completely solved.

Method used

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  • Negative electrode piece, preparation method thereof and lithium ion battery
  • Negative electrode piece, preparation method thereof and lithium ion battery

Examples

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Effect test

Embodiment 1

[0028] Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, styrene-butadiene rubber obtain the first negative electrode slurry that the gram capacity of artificial graphite is 355mAh / g by the mass percentage proportioning of 97.0%:0.5%:1.2%:1.3%, The graphitization temperature T1 of artificial graphite is 2700°C, and the OI value of artificial graphite is OI1=1.2. The first negative electrode slurry is coated on the long pasted surface of the carbon-coated copper foil of the negative electrode current collector to form a first negative electrode slurry with a thickness of 60um. Active coating; artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber are obtained by the mass percentage ratio of 97.0%: 0.5%: 1.2%: 1.3%. The gram capacity of artificial graphite is 356mAh / g. Negative electrode slurry, the graphitization temperature T2 of artificial graphite is 2750 ℃, and the OI value of artificial graphite...

Embodiment 2

[0030] Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, styrene-butadiene rubber obtain the first negative electrode slurry that the gram capacity of artificial graphite is 355mAh / g by the mass percentage proportioning of 97.0%:0.5%:1.2%:1.3%, The graphitization temperature T1 of artificial graphite is 2700°C, and the OI value of artificial graphite is OI1=1.2. The first negative electrode slurry is coated on the long pasted surface of the carbon-coated copper foil of the negative electrode current collector to form a first negative electrode slurry with a thickness of 60um. Active coating; artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber are obtained by the mass percentage ratio of 97.0%: 0.5%: 1.2%: 1.3%. The gram capacity of artificial graphite is 358mAh / g. Negative electrode slurry, the graphitization temperature T2 of artificial graphite is 2850 ℃, and the OI value of artificial graphite...

Embodiment 3

[0032]Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, styrene-butadiene rubber obtain the first negative electrode slurry that the gram capacity of artificial graphite is 355mAh / g by the mass percentage proportioning of 97.0%:0.5%:1.2%:1.3%, The graphitization temperature T1 of artificial graphite is 2700°C, and the OI value of artificial graphite is OI1=1.2. The first negative electrode slurry is coated on the long pasted surface of the carbon-coated copper foil of the negative electrode current collector to form a first negative electrode slurry with a thickness of 60um. Active coating; artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber are obtained by the mass percentage ratio of 97.0%: 0.5%: 1.2%: 1.3%. The gram capacity of artificial graphite is 360mAh / g. Negative electrode slurry, the graphitization temperature T2 of artificial graphite is 3000 ℃, and the OI value of artificial graphite ...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and relates to a negative electrode plate, a preparation method thereof and a lithium ion battery. The negative electrode plate comprises a negative current collector, a first active coating and a second active coating; the first active coating coats on a long paste coating surface of the negative current collector; the second active coating coats a short paste coating surface of the negative current collector; and the first active coating and the second active coating are both negative electrode active materials containing artificial graphite. Artificial graphite with different gram capacities is realized by controlling the graphitization temperature, and the overpotential of the long paste coating surface of the negative current collector and the diffusion impedance between the long paste coating surfaces of a positive electrode and a negative electrode are reduced by setting the artificial graphite in the first active coating and the artificial graphite in the second active coating to have different gram capacities and OI values, and therefore, the polarization of a high-voltage lithium cobalt oxide in the cycle process can be reduced, and the lithium precipitation phenomenon and the capacity retention ratio of a high-voltage lithium cobalt oxide lithium ion battery prepared by adopting the negative electrode plate in the cycle process are improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative pole piece, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium cobalt oxide material has the advantages of high voltage and high compaction density as the positive electrode material of lithium ion battery. It is an ideal positive electrode material for lithium ion battery. However, under the normal charging voltage of about 4.2V, the capacity of lithium cobalt oxide material is limited. , increasing the charging voltage of the lithium cobalt oxide battery can increase the volumetric energy density of the battery. Therefore, the research on lithium-ion batteries is now turned to high-voltage (charging voltage ≥ 4.45V) lithium cobalt oxide as the positive electrode material of lithium-ion batteries, which can increase the volumetric energy density of the battery, but the polarization is large during t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/1393H01M4/04H01M4/587H01M4/66H01M10/0525
CPCH01M4/133H01M4/1393H01M4/587H01M4/0404H01M4/661H01M10/0525H01M2004/027Y02E60/10
Inventor 於志锋梁晓静梁东建杜晨树陶德瑜
Owner 东莞维科电池有限公司
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