At present, the mainstream battery technology for electric vehicles is lithium-ion battery, which is widely used in various electric vehicle models due to its high energy density, long cycle life and high safety. Lithium-ion batteries are mainly divided into ternary lithium batteries and lithium iron phosphate batteries. Ternary lithium batteries have the advantages of high energy density, and the energy density can reach 300-400 Wh/kg, which can provide a longer range for electric vehicles. They are mainly used in mid-to-high-end electric vehicles such as Tesla, BYD Han and NIO ET5. Lithium iron phosphate batteries have the advantages of high safety and long cycle life, and the cycle life can reach more than 3,000 times, which is mainly used in low-to-medium-end electric vehicles and commercial vehicles such as BYD Dolphin and SAIC Roewe Ei5. In recent years, lithium-ion battery technology has made continuous progress. On the one hand, the energy density has been continuously improved. In 2015, the energy density of lithium-ion batteries was only about 150 Wh/kg, and by 2025, the energy density of ternary lithium batteries has reached 400 Wh/kg, and the range of electric vehicles has been increased from 200-300 kilometers to 600-800 kilometers. On the other hand, the charging speed has been continuously accelerated. The fast charging technology of lithium-ion batteries has been continuously improved, and the charging time from 0 to 80% has been shortened from 1 hour to 15-30 minutes, which has greatly alleviated users’ range anxiety. However, lithium-ion battery technology still has some problems that need to be solved. First, the cost is still high. The cost of lithium-ion batteries accounts for 30-40% of the total cost of electric vehicles, which is one of the important reasons for the high price of electric vehicles. Second, the safety needs to be further improved. Although lithium-ion batteries have high safety, there are still risks of fire and explosion in extreme cases (such as collision, high temperature, overcharging). Third, the resource shortage problem. Lithium, cobalt, nickel and other resources required for lithium-ion batteries are limited, and the large-scale use of lithium-ion batteries may lead to resource shortage in the future. Fourth, the recycling problem. The service life of lithium-ion batteries is about 8-10 years, and a large number of waste batteries will be generated in the future. If they are not properly recycled, they will pollute the environment. In order to solve these problems, major battery manufacturers and research institutions are actively researching and developing new battery technologies. The most promising new battery technologies include solid-state batteries, sodium-ion batteries and hydrogen fuel cells. Solid-state batteries use solid electrolytes instead of liquid electrolytes, which have the advantages of high energy density, high safety and long cycle life. The energy density of solid-state batteries can reach 500-600 Wh/kg, and the charging time can be shortened to 5-10 minutes. It is predicted that solid-state batteries will be put into mass production around 2028, which will greatly improve the performance of electric vehicles. Sodium-ion batteries use sodium ions instead of lithium ions, which have the advantages of low cost and abundant resources. Sodium is one of the most abundant elements on the earth, and the cost of sodium-ion batteries is about 50% lower than that of lithium-ion batteries. Sodium-ion batteries are mainly used in low-speed electric vehicles, energy storage and other fields. Hydrogen fuel cells use hydrogen as fuel, which have the advantages of zero emission, long range and fast refueling. However, the cost of hydrogen fuel cells is still high, and the hydrogen refueling infrastructure is not perfect, which limits their popularization and application. In addition, the recycling technology of lithium-ion batteries is also constantly improving. At present, the main recycling methods of lithium-ion batteries include pyrometallurgy and hydrometallurgy. Pyrometallurgy is to extract valuable metals by high-temperature smelting, and hydrometallurgy is to extract valuable metals by chemical dissolution. With the continuous improvement of recycling technology, the recycling rate of lithium-ion batteries has reached more than 80%, which can not only reduce environmental pollution, but also save resources. The future development of electric vehicle battery technology will focus on improving energy density, reducing cost, improving safety and promoting recycling. With the continuous progress of technology, it is believed that electric vehicle battery technology will make greater breakthroughs, which will promote the rapid development of the new energy automobile industry and make electric vehicles more popular among consumers.
