Lithium ferric phosphate battery adopting compound conductive agent and manufacturing method thereof

Abstract

The invention discloses a manufacturing method for a lithium ferric phosphate battery adopting a compound conductive agent. The manufacturing method comprises the following steps of: dissolving anode binder polyvinylidene fluoride in N-methyl pyrrolidone and stirring, thereby obtaining anode glue; adding a carbon nano-tube / conductive polymer compound material into the anode glue and scattering; adding anode active matter LiFePO4 and stirring, thereby obtaining anode slurry; uniformly coating the anode slurry on two surfaces of an aluminum foil, drying, and then rolling and slicing, thereby obtaining anode plates; uniformly mixing cathode active matter graphite, the carbon nano-tube / conductive polymer compound material, a cathode binder and de-ionized water, thereby obtaining cathode slurry; uniformly coating the cathode slurry on two surfaces of a copper foil, drying, and then rolling and slicing, thereby obtaining cathode slices; coiling, flatly pressing and banding, and then drying for 8 hours in vacuum at 65 DEG C; filling electrolyte into a dried battery; and forming an end product of the lithium ferric phosphate battery after filling the electrolyte. According to the manufacturing method provided by the invention, the capacity, multiplying power, circulation and safety property of the battery are greatly improved.

Description

【Technical field】 [0001] The invention relates to the field of lithium ion battery and its manufacturing process, in particular to the application of a new composite material in the manufacturing process of iron phosphate lithium ion battery. 【Background technique】 [0002] As a new generation of high-energy secondary battery products, lithium-ion batteries have outstanding characteristics such as high discharge voltage, high specific energy and specific power, small self-discharge, and long cycle life. They have been widely used in mobile communication equipment, notebook computers, instruments and meters, etc. In addition, domestic and foreign are also competing to develop the application of lithium-ion batteries in electric vehicles, aerospace and energy storage. The choice of positive electrode material greatly affects the performance of lithium batteries: the currently commercialized positive electrode materials are: LiCoO 2 , LiMn 2 o 4 , Li[Ni 1 / 3 co 1 / 3 mn 1 / 3 ...

AI Technical Summary

Problems solved by technology

[0003] Although the lithium iron phosphate power battery has many of the above advantages, it also has certain disadvantages: the electrical conductivity of the material is very low, which is not conducive to reversible reactions, especially for high-rate discharges.

Although this method can improve the conductivity of the electrode to a certain extent, it is easy to cause surface passivation when the carbon nanotubes are exposed in the air, resulting in a significant drop in conductivity; and, in order to ensure the conductivity of the pole piece, carbon nanotubes The length-to-diameter ratio requirements of the tube are relatively strict, the production cost is high, and it is not easy to operate

The patent CN102280656A discloses a preparation method of a lithium-ion battery with a conductive polymer coated positive electrode. The coating is carried out by adding a conductive polymer or a conductive polymer monomer to the slurry. Although this distribution can be improved to a certain extent The specific capacity of the battery, but the conductive polymer will cause volume shrinkage and expansion during charging and discharging, which has a serious impact and restriction on the safety performance of lithium-ion batteries

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