A lithium ion battery pole piece

A lithium-ion battery, pole piece technology, applied in battery electrodes, secondary batteries, electrode manufacturing, etc., can solve the problems of large pole piece polarization, increased compaction density, uneven pressure, etc., to improve rate performance, The effect of improving compaction density and inhibiting particle breakage

A lithium-ion battery, pole piece technology, applied in battery electrodes, secondary batteries, electrode manufacturing, etc., can solve the problems of large pole piece polarization, increased compaction density, uneven pressure, etc., to improve rate performance, The effect of improving compaction density and inhibiting particle breakage

CN111613770BActive Publication Date: 2021-05-11RISESUN MENGGULI NEW ENERGY SCIENCE & TECHNOLOGY CO LTD +1
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  • A lithium ion battery pole piece

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Example 1 is to prepare a negative electrode sheet, wherein the negative electrode current collector is 9 μm copper foil. The compacted density of the first coating layer (2) is 1.75g / cm 3 , the binder content of the first coating layer is 2.5%. The compacted density of the second coating layer (2) is 1.7g / cm 3 , the binder content of the second coating layer is 3.0%.

[0032] The thicknesses of the first coating layer and the second coating layer in Example 1 are both 70 μm.

[0033] The specific production method is as follows:

[0034] Step (1) Glue preparation:

[0035] S11: Add 2000g of water.

[0036] S12: adding a binder to make glue to obtain a glue solution.

[0037] Step (2) preparation of the first coating layer negative electrode slurry:

[0038] S21: disperse the powder, add 1349.6g of negative electrode active material and 14g of the first conductive agent (such as point-shaped conductive agent);

[0039] S22: Add 700g of second conductive agent sl...

Embodiment 2

[0058] Example 2 is to prepare a positive pole piece, wherein the positive current collector is a 15 μm aluminum foil. The compacted density of the first coating layer is 3.5g / cm 3 , the binder content of the first coating layer is 2.5%. The compacted density of the second coating layer is 3.3g / cm 3 , the binder content of the second coating layer is 3.0%. In Example 2, the thicknesses of the first coating layer and the second coating layer are both 60 μm.

[0059] The specific production method is as follows:

[0060] Step (1) Glue preparation:

[0061] S11: Add 2000g NMP.

[0062] S12: adding a binder to make glue to obtain a glue solution.

[0063] Step (2) preparation of the positive electrode slurry for the first coating layer:

[0064] S21: Dissolving PVDF in NMP solvent, stirring for 3-4 hours, preparing a glue solution with a mass percentage (solid content) of 7%, and then adding a conductive agent and positive electrode active material NCA to the glue solution ...

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Abstract

The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a lithium-ion battery pole piece, which includes a current collector (1), and is characterized in that first coating layers are sequentially arranged on both sides of the current collector (1) from inside to outside (2), the second coating layer (3), the compaction density of the first coating layer (2) is greater than the compaction density of the second coating layer (3), the bonding of the second coating layer (3) The binder content is 0.5%-1% higher than the binder content of the first coating layer (2). The invention can reduce the polarization of the pole piece, increase the lithium ion intercalation and extraction rate, improve the magnification and low-temperature performance, effectively suppress the rebound of the pole piece, and suppress the broken particles of the lithium ion battery pole piece caused by the expansion of the surface active material during the cycle.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery pole piece. Background technique [0002] In addition to the inherent properties of the active material, the microstructure of the electrode has a significant impact on the energy density and electrochemical performance of Li-ion batteries. High compaction can increase the energy density of the battery, make better contact between particles, form a better conductive network, and facilitate electronic conduction. Due to the fast running speed of the traditional lithium-ion battery pole piece during a cold pressing process, the pressure in the vertical direction of the pole piece is uneven, resulting in an increase in the compaction density perpendicular to the pole piece from the current collector to the surface, that is, the surface The coating layer has a higher compaction density and a smaller porosity, while the coating layer on...

Claims

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Application Information

Patent Timeline
11 May 2021
Publication
CN111613770B
IPC
H01M4/131; H01M4/133; H01M4/134; H01M4/136; H01M4/1391; H01M4/1393; H01M4/1395; H01M4/1397; H01M4/04; H01M10/0525
CPC
H01M4/0404; H01M4/043; H01M4/131; H01M4/133; H01M4/134; H01M4/136; H01M4/1391; H01M4/1393
Inventors
吴可; 张亚萍