Positive electrode sheet and lithium ion battery

Abstract

The application provides a positive electrode sheet and a lithium ion battery. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector, the positive electrode active material layer includes a first sublayer and a second sublayer, and the first sublayer is located on the positive electrode The outermost layer of the active material layer, the second sublayer is located between the positive electrode current collector and the first sublayer. The first sublayer includes a first positive electrode active material, the second sublayer includes a second positive electrode active material, and the first positive electrode active material is selected from single crystal or single crystal-like ternary positive electrode materials and their Coating one or more of the modified materials. The application can improve the energy density of the lithium-ion battery and reduce the gas production of the lithium-ion battery, so that the lithium-ion battery has the advantages of high energy density and good storage performance.

Description

technical field [0001] The present application relates to the field of batteries, in particular to a positive electrode sheet and a lithium ion battery. Background technique [0002] In order to pursue high-energy-density lithium-ion batteries, the positive electrode sheet is usually required to have a high compaction density. Commonly used positive electrode active materials, such as ternary positive electrode materials, are secondary particles formed by the agglomeration of primary particles, and the primary particles inside the secondary particles The bonding force between them is not strong, so the secondary particles are easily crushed and broken under pressure during the cold pressing process of the positive electrode sheet, especially the positive electrode active material particles at the contact position between the surface of the positive electrode sheet and the cold pressing roller are very easy to break, and eventually Lead to the deterioration of gas production ...

AI Technical Summary

Problems solved by technology

[0002] In order to pursue high-energy-density lithium-ion batteries, the positive electrode sheet is usually required to have a high compaction density. Commonly used positive electrode active materials, such as ternary positive electrode materials, are secondary particles formed by the agglomeration of primary particles, and the primary particles inside the secondary particles The bonding force between them is not strong, so the secondary particles are easily crushed and broken under pressure during the cold pressing process of the positive electrode sheet, especially the positive electrode active material particles at the contact position between the surface of the positive electrode sheet and the cold pressing roller are very easy to break, and eventually Lead to the deterioration of gas production of lithium-ion batteries at high temperatures

[0003] At present, in response to the above problems, the usual improvement measures are to reduce the compaction density of the positive electrode sheet to reduce the cold pressure of the cold pressure roller on the positive electrode sheet, but this method will lead to a decrease in the energy density of the lithium-ion battery, which cannot meet people's expectations High Energy Density Lithium-ion Battery Usage Requirements

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