A kind of high safety lithium ion battery and preparation method thereof

Abstract

The invention discloses a high-safety lithium-ion battery and a preparation method thereof. The positive electrode sheet of the lithium-ion battery contains a carbon-coated triphenyl phosphate flame retardant (TPP). The preparation process includes the following steps: preparing the positive electrode sheet, using extrusion The pressure coating method coats the pre-configured positive electrode slurry on the aluminum foil current collector, and makes the positive electrode sheet through baking, rolling, slitting, and die-cutting processes; the negative electrode sheet is prepared by extrusion coating. The configured negative electrode slurry is coated on the copper foil current collector, and the negative electrode sheet is made through baking, rolling, slitting and die-cutting processes. The invention can significantly improve the safety performance of the lithium-ion battery by adding the carbon-coated triphenyl phosphate flame retardant to the positive electrode sheet, and avoid unsafe problems such as fire and explosion when the battery is used under extreme conditions. Under the premise of not affecting the electrochemical performance of the battery, the internal resistance of the battery can be reduced at the same time, and the performance such as the rate of the battery can be improved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a high-safety lithium-ion battery and a preparation method thereof. Background technique [0002] With the increasing energy crisis and environmental pollution, human beings are faced with the severe challenge of developing green and renewable energy. Lithium-ion batteries have attracted much attention due to their advantages such as high energy density, no memory effect, low self-discharge rate, long cycle life, and clean and pollution-free. The development of electric vehicles powered by lithium-ion batteries has become the focus of global attention. Most countries in the world provide preferential policies and funds to support their respective related enterprises to fully develop electric vehicles in order to seize market opportunities. The performance of the power battery is the limiting factor that determines the development of electric vehicles. ...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN 104393341 A discloses an invention patent for a lithium battery high-safety electrolyte, which discloses that trimethyl phosphite is added to the electrolyte as a flame retardant, and the organic solvent is propylene carbonate (PC). The mass ratio of the flame retardant and the organic solvent in the electrolyte is 40%; although this solution has a certain effect on the flame retardancy of the battery, there are still many problems in the actual batch application

The disadvantage is that the flame retardant accounts for as much as 40% by mass in the electrolyte, and directly adding it to the electrolyte will increase the viscosity of the electrolyte, increase the internal resistance of the battery, and reduce the migration rate of lithium ions in the electrolyte , affecting the fast charge and discharge performance of the battery

At the same time, the organic solvent of the electrolyte described in this scheme is only propylene carbonate, which cannot meet the needs of the comprehensive electrochemical performance of the battery, and propylene carbonate will cause the failure of the negative electrode graphite, thereby seriously affecting the cycle performance of the battery.

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