Negative plate and lithium ion battery comprising same

Abstract

The invention provides a negative plate and a lithium ion battery comprising the same. The negative plate is formed by coating a conductive coating between a negative current collector and a first negative active material layer, so that the contact resistance between the first negative electrode active material layer and the negative electrode current collector can be reduced, the acting force between the first negative electrode active material layer and the negative electrode current collector is improved, peeling of the first negative electrode active material layer is avoided, the buffer coating is coated between the first negative electrode active material layer and the second negative electrode active material layer, the contact resistance between the first negative electrode activematerial layer and the second negative electrode active material layer can be reduced, the acting force between the first negative electrode active material layer and the second negative electrode active material layer is improved, and the transmission rate of ions and electrons is increased; and the surface of the second negative electrode active material layer is coated with the safety coating,so that the volume expansion of the second negative electrode active material layer is further buffered, the lithium dendrites can be prevented from directly piercing the diaphragm to cause internal short circuit, and the safety risk is reduced.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative electrode sheet and a lithium ion battery including the negative electrode sheet. Background technique [0002] In recent years, with the continuous expansion of lithium-ion battery industrialization and the continuous development of technology, people's requirements for lithium-ion batteries have gradually increased, and lithium-ion batteries with high energy density, long cycle life and high safety have become the research and development focus. At present, the main ways to increase the energy density of the battery are: 1. Increase the compaction density of the positive and negative electrode materials, but the high pressure will lead to low porosity of the pole piece, and the subsequent reduction of the liquid retention capacity, which will lead to insufficient cycle life of the battery; 2. Increase the gram capacity of negative electrode...

AI Technical Summary

Problems solved by technology

At present, the main ways to increase the energy density of the battery are: 1. Increase the compaction density of the positive and negative electrode materials, but the high pressure will lead to low porosity of the pole piece, and the subsequent reduction of the liquid retention capacity, which will lead to insufficient cycle life of the battery; 2. Increase the gram capacity of negative electrode materials, that is, use silicon-based negative electrode materials to replace graphite, but the large volume change of silicon-based materials during charge and discharge will cause the material to be pulverized and peeled off from the current collector, resulting in a sharp attenuation of capacity , accompanied by security issues

[0003] Existing solutions include, for example, the use of negative electrode active materials with different compaction densities to increase the liquid retention of the pole pieces while ensuring high compaction densities and increase the long cycle life; or to coat different active material layers However, these improvements have limited ability to improve battery performance, and it is urgent to develop a lithium-ion battery with high energy density, long cycle life and high safety.

Images