High-compaction negative electrode sheet and preparation method thereof and lithium ion battery comprising electrode sheet

Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a high-compaction negative electrode sheet and a preparation method thereof, and a lithium ion battery comprising the electrode sheet. The high-compaction negative electrode sheet comprises a negative electrode coating and a negative current collector, wherein the negative electrode coating comprises a negative electrode active material, an additive, a conductive agent, a suspending agent and a binder, and the additive is a high-compaction additive. According to the invention, the high-compaction additive is added into the negative electrode sheet, so that the negative electrode sheet can be stressed to slip in a negative electrode rolling process and artificial graphite particles with irregular shapes are rearranged, and relatively large gaps in the electrode sheet are filled by good flexibility so as to improve the compaction density of the electrode sheet; the high-compaction additive has the capacity characteristic equivalent to that of artificial graphite, and has no negative influence on the capacity of the negative electrode sheet; and finally, the high-compaction additive can effectively reduce the rebound of the rolled negative electrode sheet and the internal resistance of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a high-pressure compacted negative pole piece, a preparation method thereof, and a lithium ion battery containing the pole piece. Background technique [0002] Lithium-ion batteries have been widely used in the past ten years since their appearance in the last century. At present, the commonly used lithium-ion batteries are mainly composed of a metal oxide positive electrode with lithium intercalation characteristics, a graphite negative electrode, an electrolyte, and a separator. For the above-mentioned lithium-ion batteries, the manufacturing process usually includes several important steps of pulping, sheeting, assembly, and activation. In actual production, pole piece preparation is the most important link, which determines its performance and quality. [0003] At present, the most common lithium-ion battery negative electrode sheet is usually composed of four...

AI Technical Summary

Problems solved by technology

As far as the conventional use of artificial graphite anode materials is concerned, due to the influence of shape and structure, the compaction density of the anode plate usually does not exceed 1.75g / cm 3 , while other materials are limited by the amount of addition and their own structural reasons and cannot provide effective help to improve the compaction of the pole piece

If the compaction density is too large or too small, it is incorrect. If the compaction density is too small, the porosity in the pole piece is high, the active material particles are not in close contact, and the internal resistance of the battery affects the electrochemical performance of the lithium battery; compaction If the density is too high, the structure of the living material will be destroyed, there will be no enough gaps between the particles, the internal repulsion force will be too large, and the thickness will rebound after rolling.

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