Nanometer lithium iron phosphate power cell with super-high rate and super long cycle life and manufacturing method

Abstract

A nanometer lithium iron phosphate power cell with super-high rate and super long cycle life and a manufacturing method thereof. Based on weight percentage, the manufacturing method comprises the following steps of: 1) controlling environmental humidity; 2) preparing a LFP premixing liquid; 3) carrying out sand milling; 4) carrying out high magnetic filtering; 5) filtering by a filter; 6) preparing a glue solution; 7) preparing a slurry; 8) coating carbon aluminium foil and pole shoe coating; 9) processing the pole shoe by a hot roller; 10) baking in vacuum; 11) examining. The processed and manufactured nanometer lithium iron phosphate cell provided by the invention has much more excellent internal resistance, cycle performance, high rate discharge performance and low temperature performance than cells manufactured by common technologies; the self-discharge rate of the cell provided by the invention is much lower than that of the cells manufactured by common technologies; the cycle life of the cell provided by the invention at high rate is increased from 2000 times to over 8000 times; and the properties of the cell provided by the invention can all meet requirements of cells for electric vehicles and racing cars.

Description

technical field [0001] The invention relates to the technical field of manufacturing lithium-ion secondary batteries, in particular to a nano-lithium iron phosphate power battery with ultra-high rate and ultra-long cycle life and a manufacturing method thereof. Background technique [0002] Lithium iron phosphate power battery is a new generation of lithium-ion secondary battery. The main elements iron and phosphorus in lithium iron phosphate are not only abundant in nature, but also relatively cheap, environmentally friendly, and superior in performance. For pure electric vehicles , The large-scale popularization of hybrid electric vehicles is of great significance; lithium iron phosphate power battery has a stable olivine structure, so it is very safe; through the nanometerization of lithium iron phosphate cathode material and doping with metal elements, the lithium iron phosphate power battery has Very good high-rate performance; through the improvement of the purity of t...

AI Technical Summary

Problems solved by technology

[0003] Current problems: Because power batteries have higher and higher requirements on performance such as rate, the original particle size of the positive electrode material used in the production of the battery is getting smaller and smaller, and even nanometerized, and the nanometerized lithium iron phosphate positive electrode material has great Strong water absorption, once the water is absorbed and polluted by water, the crystal water and bound water of the positive electrode material in the battery cannot be baked out with the traditional temperature and vacuum degree of the baking material. During the later use of the battery, the bonding fastness between the nano-sized powder and the ordinary aluminum foil cannot meet the process requirements, and it is difficult to make the nano-sized lithium iron phosphate powder using the traditional mixing method and battery manufacturing process. The materials are evenly dispersed, resulting in battery rate performance, cycle performance, low temperature performance, and cell consistency, which cannot meet the requirements of batteries for electric vehicles.

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