A kind of fast charge and discharge high voltage lithium ion battery and preparation method thereof

Abstract

The purpose of the present invention is to provide a high-voltage lithium-ion battery capable of rapid charging and discharging and a preparation method thereof. The battery includes a negative electrode, a positive electrode, a diaphragm between the positive and negative electrodes, and a non-aqueous electrolyte, and the charging cut-off voltage is raised to 4.35V. The energy density of the battery is greatly improved. The present invention is characterized in that the negative electrode material takes graphite as the core, and the graphite surface is evenly coated with a layer of lithium titanate, and then a layer of conductive agent is coated on the surface of graphite particles coated with lithium titanate to form graphite-lithium titanate-conductive agent three-layer composite structure. The manufactured battery has very good fast charging and discharging performance, and the high and low temperature performance has been greatly improved, and the safety performance has also been greatly improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a fast-chargeable high-voltage lithium-ion battery and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the characteristics of high specific capacity, small self-discharge, wide operating temperature range, high voltage platform, long cycle life, no memory effect, and environmental friendliness. They have been widely used in mobile phones, notebook computers, power tools and other fields. And gradually promote in the field of electric vehicles. At present, important cities such as my country's Beijing, Tianjin, Shenzhen, and Shanghai have built charging stations for hybrid electric vehicles and pure electric vehicles. However, according to the current charging method of lithium batteries, electric vehicles often need 7-8 hours for a single charge; while consumer electronics such as mobile phones, laptop batteries, and electric ...

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Problems solved by technology

[0003] In recent years, some studies have achieved the purpose of fast charging by setting a number of regular small holes on the positive electrode sheet, but the actual application of this method consumes more materials and time; some studies have used submicron lithium titanate and lithium metal oxide to coat graphite , Composite lithium metal oxide-coated graphite, graphite-coated lithium titanate and other materials are used as negative electrodes to achieve fast charging effects, but there are problems such as low energy density of lithium titanate and low conductivity of lithium metal oxide, while titanium The rate performance of lithium acid is poor, and the battery cell made is easy to produce gas, and the high temperature performance is poor

And the current research on fast charging shows that the charging cut-off voltage of the battery cell is only 4.2V, and the energy density is low.

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