Forming method of positive pole piece of lithium ion power battery

Abstract

The invention discloses a forming method of a positive pole piece of a lithium ion power battery. A big positive pole piece roll is symmetrically and continuously coated with blank middle; coating regions are located on positive and negative faces of a pole piece body, are symmetrical in position, and share pole tabs led out of blank middle regions; and eudipleural blank regions are arranged on the two sides of the coating regions. Forming of the positive pole piece adopts integral fillet cutting die punching design, the pole piece adopts rotary compact distribution, and safe boundaries are arranged at the heads and the tails of the coating regions, so that a foil material is utilized to the greatest extent, and the material cost of the battery is lowered. Fillet design avoids upturning and deformation of corners of the pole piece, and the assembling efficiency and the safety performance of the lithium ion battery are further improved. The method can effectively reduce the probability of an internal short circuit due to the fact that a pole piece edge burr generated by die cutting pierces a membrane of the battery; a powder falling phenomenon of dressing in a next manufacturing process is greatly reduced; self-discharge of a battery cell is reduced; and the electrical performance and the safety performance of the battery are improved.

Description

Technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a method for forming a positive pole piece of a lithium ion power battery with high safety. Background technique [0002] Lithium-ion batteries have the advantages of high voltage, high specific energy, many cycles of use, and long storage time. They are widely used in electric vehicles, energy storage, power tools and other fields. With the large-scale application of lithium-ion batteries, safety issues have gradually increased More and more manufacturers are paying attention. In the existing lithium-ion battery production, the structure design of the positive and negative pole pieces has certain defects, which are likely to cause safety accidents, especially the positive pole pieces. For example, in the production process of the positive electrode sheet of the battery, the electrode sheet needs to be die-cut. On the one hand, gap coating is often used in the coating of the exi...

AI Technical Summary

Problems solved by technology

On the one hand, gap coating is mostly used in the coating of existing positive electrodes, but due to the surface tension of slurry and other reasons, gap coating faces problems such as uneven thickness of the head and tail, difficulty in aligning the front and back sides, and non-parallel heads and tails. As a result, die-cutting is difficult, the yield of pole pieces is low, the utilization rate of foil is low, and the cost of battery manufacturing is high

On the other hand, the existing die-cutting technology all cuts from the dressing area. When cutting, the dressing at the edge of the coating area and the tail is easy to fall off. Once the peeling dressing pierces the battery separator, it will cause an internal short circuit of the battery cell, seriously affecting the battery life. Safety performance, and increase the self-discharge of the cell

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