Microporous diaphragm of external coating of lithium ion battery and matching coating slurry formula

Abstract

The invention discloses a microporous diaphragm of an external coating of a lithium ion battery. The microporous diaphragm is adopted as a base material, and a coating is arranged on two planes of themicroporous diaphragm respectively. Each coating is a conductive coating, and the thickness of the dried coating is 1-5mu m. A matching coating slurry formula is prepared from the following components in percentage by weight: 1-10% of adhesive, 1-5% of dispersing agent, 75-87% of solvent and 5-20% of carbon material. The carbon material is a one-dimensional carbon material, or a two-dimensional carbon material or both; the one-dimensional carbon material comprises a carbon tube and carbon fiber; the two-dimensional carbon material comprises graphene and flake graphite; by applying the microporous diaphragm and the matching coating slurry formula disclosed by the invention, the cycle life of the lithium ion battery can be remarkably prolonged. The microporous diaphragm disclosed by the invention is suitable for matching lithium ion batteries with various specifications and is mounted like a diaphragm in the prior art, and does not need additional investment or change of the lithium ionbattery production line by a manufacturer.

Description

technical field [0001] The invention relates to a membrane for a lithium ion battery. Specifically, the invention relates to a microporous diaphragm for an external coating of a lithium ion battery for a lithium ion battery. The invention also relates to a matching coating slurry formula. Background technique [0002] The positive and negative electrodes of the lithium-ion battery are separated by a separator, and the separator made of polyolefin is used as an insulator in the battery structure, so that electrons in each direction cannot pass through. In order to further improve the electrochemical reaction efficiency of lithium-ion batteries, the industry prefers to use microporous separators. In addition to retaining the original electronic insulation function of this kind of separators, the preset micropores facilitate the free passage of ions. The sheet electrodes of lithium-ion batteries are processed by rolling. From a macroscopic point of view, the surface of the shee...

AI Technical Summary

Problems solved by technology

The sheet electrodes of lithium-ion batteries are processed by rolling. From a macroscopic point of view, the surface of the sheet electrodes is relatively smooth, but from a microscopic point of view, the surface is uneven. Therefore, the separator between the positive and negative electrodes is easily worn, resulting in Partial overcharge or overdischarge occurs in the charging and discharging process of lithium-ion batteries, which accelerates the degradation of battery performance and even poses safety hazards

Facing the above practical problems, the industry currently has no suitable solutions, so the cycle life of lithium-ion batteries made with existing technologies is difficult to meet expectations

Images