Composite lithium membrane and lithium ion battery pole piece of diaphragm and preparation method thereof

Abstract

The invention discloses a composite lithium membrane and a lithium ion battery pole piece of a diaphragm. By compositing the lithium membrane at two sides of the battery pole piece, first efficiency of the battery pole piece after the battery is produced is increased, irreversible capacity in the battery is decreased, energy density is increased; at the same time, the diaphragm is composited at outside of the lithium membrane, influence of environment on the lithium membrane can be effectively protected, and safety is greatly increased. The invention also provides a method for preparing the composite lithium membrane and the lithium ion battery pole piece of the diaphragm, by prefabricating a lithium membrane composite sheet, security during production is guaranteed, through a stitching mechanism, a lithium membrane lamination step is realized during a winding process of the battery pole piece, winding difficulty is greatly reduced, and the winding efficiency is enhanced.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a lithium-ion battery pole piece with a composite lithium film and diaphragm and a preparation method thereof. Background technique [0002] With the explosive development of the new energy automobile industry, the demand for lithium-ion batteries is growing rapidly. According to the national plan for power batteries in 2020, by 2020, the energy density of a single power battery must reach 300Wh / Kg. To achieve this energy density, it is generally believed that silicon or silicon-carbon composite materials should be used as the negative electrode. However, the first-time efficiency of batteries made of this material as the negative electrode is low, which affects the improvement of energy density. [0003] The current idea is to supplement lithium elements on the surface of the negative electrode, and the SEI film can be formed as a lithium source when the battery i...

AI Technical Summary

Problems solved by technology

However, the efficiency of the first battery made of this material as the negative electrode is low, which affects the improvement of energy density.

[0003] The current idea is to supplement lithium elements on the surface of the negative electrode, and the SEI film can be formed as a lithium source when the battery is charged for the first time, so that the lithium ions in the positive electrode are completely used for reversible deintercalation reactions, improving the first efficiency and energy density, but Its lithium is an extremely active metal, and it will burn and explode when it meets water, which poses a great safety hazard, the manufacturing process is complicated, and it is difficult to realize engineering

Images