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Lithium battery pole piece coating method

A coating method and technology for lithium batteries, applied in battery electrodes, electrode manufacturing, circuits, etc., can solve the problems of high cost, unfavorable performance of lithium batteries, and low efficiency.

Active Publication Date: 2021-04-20
EVE ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problems in the above technical solution are: 1. Secondary processing of the foil and diaphragm is required separately, which is low in efficiency and high in cost; 2. The slurry coating of the positive / negative electrode active material needs to be rolled after the carbon-coated foil treatment, the pore distribution of the coating layer after rolling presents a state of loose interior and tight exterior, which is not conducive to the performance of lithium batteries

Method used

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  • Lithium battery pole piece coating method
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Examples

Experimental program
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Effect test

Embodiment 1

[0030] The B slurry in Example 1 and Example 2 was used to prepare the positive electrode sheet, and the B slurry in Example 3 and Example 4 was used to prepare the negative electrode sheet.

[0031] C slurry includes PVDF, second solvent. The second solvent may be a compound having a relatively strong dipole moment, such as dimethylformamide, dimethylsulfoxide, dimethylacetate, acetone, and N-methyl-2-pyrrolidone (NMP). In particular, NMP is preferred since a large amount of γ-phase crystalline compounds can be obtained using NMP. The mass ratio of PVDF to the second solvent is 1:0.1-100. If the ratio of the second solvent is less than 0.1, PVDF cannot be sufficiently dissolved and cannot be used as a binder. If the ratio of the second solvent exceeds 100, PVDF dissolves sufficiently, but the solution concentration of the active material is too low, reducing the binding effect.

[0032] The C slurry described in Examples 1-4 is configured by PVDF and NMP at a mass ratio of...

Embodiment 2

[0044] This embodiment provides a method for coating lithium battery pole pieces. The only difference between this embodiment and Embodiment 1 is that in this embodiment, the content of dispersant in A slurry is 1wt%, and the content of graphene flakes is 10wt. %.

Embodiment 3

[0046] This embodiment provides a method for coating a lithium battery pole piece. The method is to prepare a negative pole piece by coating A slurry, B slurry, and C slurry on a copper foil through a multi-layer slide coating process. Where B slurry includes B 1 slurry, B 2 slurry, B 3 slurry. B 1 Coating thickness of slurry, B 2 Coating thickness of slurry, B 3 The coating thicknesses of the pastes were all the same. After the negative electrode sheet prepared in this example is dried, the B layer includes B 1 Layer, B 2 Layer, B 3 Layer, B 1 Layer and A layer are connected, B 3 Layer and C layer are connected.

[0047] B 1 In the slurry, the binder content is 10wt%, the solid content (comprising negative electrode active material and conductive additive) is 50wt%, and the surfactant content is 0.1wt%, B 2 In the slurry, the binder content is 9.9wt%, the solid content is 49wt%, and the surfactant content is 0.2wt%, B 3 The binder content in the slurry is 9.8wt%...

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Abstract

The invention relates to a lithium battery pole piece coating method, which comprises the step of synchronously coating conductive carbon layer slurry, lithium battery slurry and PVDF (Polyvinylidene Fluoride) glue solution slurry on the surface of a foil from inside to outside through a multi-layer slope flow coating process. According to the lithium battery pole piece coating method provided by the invention, the pore distribution of the coating layer of the prepared positive / negative pole piece can be optimized, a positive pole piece and a negative pole piece prepared by the method provided by the invention can be matched and assembled with an existing common diaphragm to form a lithium battery cell, and the lithium battery cell has relatively good wettability and rate charge-discharge performance.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a method for coating lithium battery pole pieces. Background technique [0002] At present, the coating process is commonly used in lithium batteries to coat the slurry including positive / negative active materials on the current collector to prepare positive / negative electrode sheets. The positive electrode current collector generally uses aluminum foil, and the negative electrode current collector generally uses copper foil. In order to effectively reduce the contact resistance between the positive / negative electrode active material and the current collector, reduce the expansion of the active material during the high-rate cycle of the lithium battery, and improve the high-rate discharge voltage and rate cycle performance of the battery, the existing technology The scheme is: the current collector is made of carbon-coated foil, and the slurry including positive / negative active m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/139
CPCY02E60/10
Inventor 殷军何巍曾汉民甘祖涛阳铮刘金成刘建华
Owner EVE ENERGY CO LTD
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