Lithium ion battery positive pole pieceand preparation method thereof

Abstract

The invention provides a lithium ion battery positive pole piece, which comprises a positive current collector, a conductive coating layer and an active slurry layer, wherein the conductive coating layer and the active slurry layer are sequentially coated on the positive current collector, and the active slurry layer comprises, by mass, 95% of a LiFePO4 active substance, 2.8% of a conductive agent and 2.2% of a binder; the conductive coating layer comprises the following components in percentage by mass: 10% of a conductive agent, 2% of a binder, 1% of ethanol, 1% of acetone and 86% of deionized water; the binder is polyvinylidene fluoride, the conductive agent is conductive carbon black, and the positive active substance is LiFePO4. The preparation method is simple, the conductivity of the pole piece can be effectively improved, the lithium ion transfer impedance in the battery is obviously reduced, the direct-current internal resistance of the battery is obviously reduced, and the cycling stability of the battery can be improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery positive electrode sheet and a preparation method thereof. Background technique [0002] Lithium ions have the advantages of high energy density, light weight, high voltage, and environmental protection, so they are widely used in mobile phones, digital cameras, UPS power supplies, and electric vehicles. Among them, lithium iron phosphate batteries have stable voltage platform, good cycle performance, and abundant raw materials, which have become the most promising positive electrode materials at present. However, due to the unique olivine structure of lithium iron phosphate batteries, the transmission rate of electrons and ions is low, so it is necessary to add a conductive agent to improve its conductivity. [0003] Conventional positive electrode conductors include SP, CNTs, etc., and binders include HSV900, Solef-5130, etc. When the positive electr...

AI Technical Summary

Problems solved by technology

When the positive electrode slurry prepared by the above system is coated on the current collector, most of the conductive agent floats on the surface of the pole piece due to poor dispersion effect and weak bonding ability of the binder, resulting in poor conductivity of the pole piece. Thus increasing the DC internal resistance of the battery and reducing the cycle performance of the battery

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