Lithium ion battery and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery and a preparation method thereof, and the method comprises the following steps: respectively preparing a positive pole piece, a negative pole piece and a diaphragm, and winding the positive pole piece, the negative pole piece and the diaphragm into the lithium ion battery; the preparation method of the positive pole piece comprises the following steps: coating a plurality of positive slurry layers and insulating coatings in the width direction of a positive current collector at intervals to form coated positive pole piece strips; and cutting the coated positive plate strip along the center line of the insulating coating in the length direction of the positive current collector to form a plurality of positive plates. The preparation method of the lithium ion battery can realize higher efficiency; the head and tail of the naked battery cell of the prepared lithium ion battery cannot be warped, the problem of lithium separation or incomplete lithium embedding at the edge of the pole piece cannot occur, the positive pole piece and the negative pole piece cannot be staggered in the falling process of the lithium ion battery, and the safety performance of the lithium ion battery is further improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery and a preparation method thereof. Background technique [0002] As soft-pack lithium-ion batteries become more and more widely used, cells with high safety and long cycle life have good market competitiveness. During the winding process of the existing conventional structure, the pole pieces of the single-sided area will be folded. The width of the positive and negative pole pieces is different. The width of the negative pole piece is greater than the width of the positive pole piece. The edge of the chip will affect the edge insertion of lithium, and the edge of the cell will be precipitated during the charging and discharging process. At the same time, the pole piece will slide during the falling process of the cell, which will cause safety problems. [0003] In view of this, it is indeed necessary to provide a technical solution...

AI Technical Summary

Problems solved by technology

[0004] One of the objectives of the present invention is to provide a lithium-ion battery and a preparation method thereof in view of the deficiencies in the prior art. The positive electrode sheet can balance the tension on both sides of the positive electrode sheet by providing an insulating coating on the outside of the positive electrode slurry layer. , so that the head and tail of the bare cell will not be warped, and the part of the negative pole piece that exceeds the edge of the positive pole piece is replaced by an insulating coating, so that the edge of the pole piece will not have the problem of lithium precipitation or incomplete lithium insertion.

Images