Lithium-ion batteries have been widely used in portable electrical appliances such as laptops, video cameras and mobile communications for their unique performance advantages. The large-capacity lithium-ion battery developed has been tested in electric vehicles and is expected to become one of the main power sources for electric vehicles in the 21st century, and will have applications in artificial satellites, aerospace and energy storage. With the shortage of energy and the pressure of environmental protection in the world. Lithium is widely used in electric vehicle industry, especially the appearance of lithium iron phosphate battery, which promotes the development and application of lithium battery industry.