Lithium ion battery with high energy density and preparation method of lithium ion battery with high energy density

Abstract

The invention relates to the technical field of lithium ion batteries and in particular relates to a lithium ion battery with the high energy density and a preparation method of the lithium ion battery with the high energy density. The lithium ion battery comprises a positive electrode, a negative electrode, an isolation film and electrolyte, wherein the positive electrode comprises a positive current collector, an active material A layer and an active material B layer; the active material A layer is arranged between the positive current collector and the active material B layer; the particle diameter of an active material B is greater than that of an active material A; the weight ratio of the active material A layer to the active material B layer is 0.1-10; the negative electrode comprises a negative current collector, a conductive polymer C layer and a negative film; the conductive polymer C layer is arranged between the negative current collector and the negative film; the thickness of the conductive polymer C layer is less than or equal to 5 microns. The lithium ion battery prepared by adopting the method is relatively high in dynamics performance; the problem of risk of separating lithium out of a thickly-coated system lithium ion battery at the low temperature can be effectively solved. The prepared battery is safe, reliable, and long in cycle life.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery with high energy density and a preparation method thereof. Background technique [0002] Since its commercialization, lithium-ion batteries have been widely used as power sources for various mobile devices due to their high energy density, high working voltage, no memory effect, long cycle life, and no pollution to the environment. The practical phase of the scale. [0003] With the progress of society, many portable devices are moving toward intelligence and multi-function. In order to meet their capacity and power requirements and ensure sufficient practical time, their power sources must have higher energy density. So far, the improvement of energy density mainly comes from the development and application of high energy density materials and the excavation and application of limited space by process improvement. However, the practical elect...

AI Technical Summary

Problems solved by technology

So far, the improvement of energy density mainly comes from the development and application of high-energy-density materials and the excavation and application of limited space by process improvement. However, the practical electrochemical system of lithium-ion batteries is basically fixed so far, which restricts the further improvement of its energy density.

On the other hand, in terms of lithium battery processing and production, the application of thinner diaphragms and current collectors is approaching the technical bottleneck, and it is difficult to break through in the short term

[0004] In order to increase the energy density, some developers try to increase the surface density of the coating film. However, after the surface density increases, the diffusion path of lithium ions increases significantly, and the mass transfer resistance increases, which makes it difficult to meet the application requirements.