Lithium iron phosphate flexible packed lithium ionic cell

Abstract

The invention relates to a lithium ion battery flexibly packaged by lithium iron phosphate; a formula of an electrolyte comprises the following compositions: LiBOB, PS, BS, EC, PC, EMC, LiPF6 and VC; an anode material comprises the following compositions: LiFePO4, carbon black, an adhesive and a conduction agent; and a cathode material comprises the following compositions: graphite, carbon black and an adhesive. The lithium ion battery optimizes the electrolyte, improves the capacity and the safety performance of the battery on the basis of ensuring the electrochemical performance of the battery; the improvement of the anode material and the cathode material solves the problems of poor self conduction of the lithium iron phosphate, environmental protection and cost; in a preparation process, the preparation of an anode slurry and a cathode slurry, the anode coating environment and a process of the electrode rolling course are improved; and the lithium ion battery flexibly packaged by the lithium iron phosphate has the advantages of large capacity, high safety, high cost performance, environment-friendliness and the like.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a lithium iron phosphate soft-pack lithium ion battery. Background technique [0002] Lithium-ion batteries have the characteristics of high voltage, high specific energy, long cycle life, and low self-discharge rate. However, based on the unique electrochemical working principle of lithium-ion batteries and the inherent characteristics of electrodes and electrolyte materials, lithium-ion batteries also have some shortcomings, which can be summarized as follows: [0003] Safety issues during high current charging and discharging (that is, in use). First of all, during the charging process, lithium ions are deposited on the protective film, which will gradually form dendritic crystals. During the discharge process, the dendrites will dissolve, but they cannot be completely dissolved, and the remaining crystals will continue to crystallize and grow during the next charge. In the end, it ...

AI Technical Summary

Problems solved by technology

[0011] Although lithium iron phosphate power battery has a series of incomparable advantages of other materials, it also has some shortcomings, mainly in: (1) the battery capacity is low, and the safety performance needs to be improved; (2) pure LiFePO 4 Poor electrical conductivity and ion diffusion performance of the battery lead to poor high-current discharge performance of the battery, and the binder of the existing electrode material is a polymer of vinylidene fluoride (PVDF), and its volatilization not only pollutes the environment, but also endangers the health of operators , In addition, PVDF is expensive, which increases the production cost of lithium-ion batteries; (3) LiFePO 4 The bulk density and tap density are relatively low, which makes it difficult to coat the positive electrode slurry in the production process