Preparation method of high-flame-retardancy lithium ion battery

Abstract

The invention discloses a preparation method of a high-flame-retardancy lithium ion battery. The preparation method comprises the steps of: evenly mixing a positive electrode active substance and a flame retardant, adding a conductive agent, PVDF and NMP into the mixture, kneading and stirring the mixture to obtain a positive electrode slurry, and coating the positive electrode slurry on aluminumfoil to obtain a positive electrode pole piece; evenly mixing a negative electrode active substance, a conductive agent, SBR, CMC and water to obtain a negative electrode slurry, coating the negativeelectrode slurry on copper foil to obtain a negative electrode pole piece; winding the positive electrode pole piece, the negative electrode pole piece and a membrane into a pole group, and manufacturing the pole group into a lithium ion battery after performing operations such as baking, shell entering, electrolyte injection, aging and formation on the pole group. According to the preparation method, the flame retardant is directly added into to the positive electrode slurry, and the combustion reaction can be inhibited or prevented by physical or chemical means after thermal runaway of the battery occurs; the flame retardant only forms a film at the positive electrode without loss at the negative electrode, thus the additive amount of the flame retardant is reduced, and the lithium precipitation situation of the negative electrode of the battery is reduced to a certain extent; and since the ignition point of the flame retardant is high, the addition of the flame retardant into the positive electrode slurry does not affect the original performance such as the cycle performance and processing performance of the battery.

Description

technical field [0001] The invention relates to a preparation method of a lithium ion battery, in particular to a preparation method of a highly flame-retardant lithium ion battery. Background technique [0002] Due to its high specific capacity, small self-discharge, wide operating temperature range, high voltage platform, long cycle life, no memory effect, and environmental friendliness, lithium-ion batteries have been widely used in electric vehicles, energy storage, digital electronic products, etc. However, the safety performance of lithium batteries is still an important issue affecting their commercial applications. [0003] At present, the electrolytes of common lithium-ion batteries on the market are mostly organic liquid electrolytes, which are composed of conductive lithium salts, organic solvents and some specific additives. Commonly used organic solvents are mostly alkyl carbonate compounds, such as: diethyl carbonate (DEC), propylene carbonate (PC), ethylene c...

AI Technical Summary

Problems solved by technology

However, the direct addition of flame retardants to organic liquid electrolytes will increase the viscosity and deteriorate the ionic conductivity, increase the polarization effect inside the lithium battery, deteriorate the cycle performance of the lithium battery, and aggravate the lithium precipitation at the negative electrode. Limiting the application of flame retardants in lithium batteries

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