Preparation method of high-capacity 18650 lithium iron phosphate battery

The invention provides a preparation method of a high-capacity 18650 lithium iron phosphate battery. The preparation method comprises the following steps: step 1, homogenizing; step 2, coating; step 3, rolling; step 4, slitting; and 5, winding. The positive electrode material LiFePO4 used in the invention is relatively low in price and has the advantages of environmental friendliness, long cycle service life, high safety and the like, and compared with other positive electrode materials, the material cost can be reduced by about 20-50%; positive and negative active materials respectively adopt carbon-doped coated lithium iron phosphate and graphite materials which are small in particle, uniform in distribution, high in specific capacity and high in compaction, a positive active supplement lithium material does not need to be added, and the energy density is increased by more than 20%; the single-walled carbon nanotube CNT composite material with excellent conductivity is adopted, so that the consumption of a