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Negative electrode plate and lithium ion battery

A lithium-ion battery and negative electrode technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of poor high-rate charge and discharge performance, thin thickness, large porosity, etc., to improve energy density and improve safety performance , the effect of small compaction density

Pending Publication Date: 2021-12-03
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the technical problems of capacity development and high-rate charge-discharge performance of the negative electrode sheet in the prior art, especially the poor capacity performance and large-rate charge-discharge performance of the negative electrode sheet with a thick coating, that is, high energy density, the application provides A negative electrode sheet and a lithium ion battery, by setting a porous diffusion layer with large porosity and thin thickness in the coating of the negative electrode sheet, on the one hand, it will not affect the energy density of the negative electrode sheet as a whole, and on the other hand, the porous diffusion layer can also be used for Store the electrolyte, which is beneficial to the transmission of lithium ions in the coating, so that lithium ions can be quickly transported to the adjacent active material layer, thereby improving the high rate charge and discharge performance of the battery, and also making the capacity of the active material fully The performance of the battery further improves the energy density of the battery

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0053] Coating the negative electrode sheet was prepared in a manner the through hole, do not particularly limited, is obtained just meet holes throughout the coating can be. Laser drilling may be used, may also be employed for the metal needle rolling pore, the distance between the diameter of the hole is the diameter of the metal needle is a metal needle is the hole spacing. A second aspect, the present application provides a method for preparing the negative electrode sheet, an active layer comprising preparing a slurry, the porous diffusion layer slurry, the slurry is coated on the active layer surface of the current collector, dried and then treated porous coating diffusion layer slurry, by dry processing, and then coated with an active layer slurry, the negative electrode sheet according to the number of layers and the porous active layer is coated diffusion layer is required, only that the porous diffusion layer in the active layer between two adjacent can, after completion...

Embodiment 1

[0065] Preparing a porous diffusion layer: 1g of graphene oxide, mixed 0.2g of UDMH dissolved in 800ml distilled water under stirring, 0.2g 35% aqueous ammonia and then hydrated mass ratio of the mixed solution was added with stirring, at 100 water bath for 30 min at ° C; followed by addition of 1g of artificial graphite negative electrode, ultrasonic dispersion 20min. Cool to room temperature and filtered, to obtain graphene oxide mixed with artificial graphite hydrogel films, the hydrogel film of this mixture was immersed in a 10% aqueous solution of lithium nitrate in mass ratio of 12 hours, and then dried at 100 degrees Celsius for 24 hours, and then washed with water (remaining in the washed and dried solid lithium nitrate bore), and dried to obtain a porous diffusion layer having a graphene oxide support. The average pore size of the porous diffusion layer is 1.2nm, a porosity of 30%. Wherein the graphene oxide reduction UDMH with good electrical conductivity, such that the ...

Embodiment 2

[0070] Unlike Example 1, the prepared porous diffusion layer, as a replacement artificial graphite G 50-300 nm diameter carbon-coated silicon powder alkylene oxide, the obtained porous diffusion layer comprises a silicon oxide negative active material, ethylene, pores of the porous layer was 23%.

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PUM

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Abstract

The invention provides a negative electrode plate which comprises a current collector and a coating arranged on the surface of the current collector, the coating comprises at least two active layers and a porous diffusion layer arranged between the two adjacent active layers, the porosity of the porous diffusion layer is larger than that of the adjacent active layers, and the thickness of the porous diffusion layer is smaller than that of the adjacent active layer. According to the negative electrode plate with the structure, the porous diffusion layer with large porosity and thin thickness is introduced between the active coatings of the negative electrode plate, so that the overall energy density of the negative electrode plate is not influenced, the transmission of lithium ions in the coatings is facilitated, the high-rate charge-discharge performance of the battery can be improved, and the capacity of the active material in the negative electrode plate can be fully exerted, so that the energy density of the battery is further improved.

Description

Technical field [0001] The present application relates to the field of lithium-ion batteries, in particular, to a negative electrode sheet and a lithium ion battery. Background technique [0002] As the lithium-ion battery is widely used, people have a growing pursuit of their energy density and magnification performance. The existing lithium-ion battery is used as a negative electrode active material in a plurality of graphite or silicon carbon. In order to increase the energy density of the battery, it is often used to increase the thickness of the coating in the negative electrode sheet by increasing the amount of negative electrode active material applied in the negative electrode. The compaction density of the negative electrode sheet is realized, but the thickness of the coating and the compaction density can cause the electrolyte to be more difficult to penetrate to the coating, in particular, the portion of the concentrated fluid, so that the lithium ion is in the coating...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/133H01M4/134H01M10/0525H01M4/02
CPCH01M4/133H01M4/134H01M10/0525H01M4/02H01M2004/021Y02E60/10
Inventor 张柯马永军郭姿珠
Owner BYD CO LTD
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