Electric car will lift a new wave of "lithium power"

On June 15, Shenzhen Liye Group, one of the world's largest manufacturers of lithium-ion polymer batteries, built the largest lithium-ion battery base in western China in Chongqing’s Liangjiang New District.

It is reported that the total investment of the industrial park is 3.5 billion yuan. After the completion of the project, the cylindrical production capacity of 18650 batteries will reach 100,000 units per day, the power battery capacity will be 320,000 units per day, and the annual production value will reach 1 billion ampere-hours. The battery output is sufficient to supply 5000 electric buses, 100,000 electric cars, 1 million electric motorcycles and electric bicycles.

Data show that lithium-ion batteries are new, environmentally friendly energy storage and secondary supply equipment. Lithium-ion batteries have high energy density and high average output voltage. Self-discharge is small, less than 10% per month, and there is no memory effect. The operating temperature range is -20 degrees Celsius to 60 degrees Celsius. Excellent cycle performance, rapid charge and discharge, charging efficiency up to 100%, and large output power, long service life, no environmental pollution, known as the green battery.

Lithium-ion batteries have been widely used in laptop computers, video cameras, and mobile communications due to their light weight, small size, long cycle life, and good safety performance.

At present, large-capacity lithium-ion batteries are used as the main energy supply equipment in electric vehicles. Power applications require much more stringent battery requirements. The application of lithium-ion batteries in automobiles is different from that in other applications. The complex application environment in automobiles imposes higher requirements on batteries, such as working in high-temperature, humid, and vibration environments. Although the application of energy in electric bicycles is not as good as that of automobiles, the requirements for adapting to the environment are not low.

In addition, lithium-ion batteries also have the characteristics of low energy consumption and long cycle life. Under the same conditions, lithium-ion batteries consume only one-third of the resources of lead-acid batteries, and their service life is three to four times longer. .

Now, if the energy density of batteries used in electric vehicles or hybrid cars is too high, there will be some safety problems, if the operating temperature is too high or strong vibrations, etc. may cause circuit system failure.

According to a recent report by the Massachusetts Institute of Technology’s “Technical Review” magazine, the United States’s Leiden Energy Corporation has developed a new type of lithium battery that can safely work at high temperatures on the basis of higher energy density than existing lithium batteries. It is very suitable for electric cars.

Leiden Energy replaces the aluminum current collectors and lithium hexafluorophosphates used in traditional battery electrolytes with graphite current collectors and sodium imide, which increases battery life while working well at temperatures above 60 degrees Celsius. Moreover, the new battery has a 50% higher energy density than the lithium ion used in electric vehicles.

The new battery replaces lithium hexafluorophosphate with sodium imide. Lithium hexafluorophosphate reacts with the water inside the battery. This reaction will significantly reduce the life of the battery. The sodium imide will not react. Lithium hexafluorophosphate decomposes at room temperature and its efficiency decreases significantly at 55 degrees Celsius, and imide sodium does not decompose at higher temperatures.

However, sodium imide can also cause trouble. It can corrode aluminum current collectors that are common in batteries. Therefore, Leiden uses graphite that can resist such corrosion.

The new battery can be cooled with air coolant without the use of liquid coolant, which will reduce costs and make the battery lighter. The company is also developing battery management electronics and software to prevent overcharging or undercharging problems that could cause the battery to “live”.

According to estimates, the current global demand for electric vehicles for lithium-ion batteries accounts for 10%. It is expected that this proportion will rise to 75% in the next five years and the market is very large.

In the long run, price is not a problem that restricts the development of power lithium-ion batteries. At present, the main factors constraining the development of power lithium-ion batteries are the further development of technologies to improve battery life and eliminate people's concerns about their safety and product maturity.