The main components of new energy electric vehicles are power batteries, electric motors and energy conversion control systems. Power batteries need to achieve high performance, such as fast charging and safety. They are the highest technical threshold and the most profitable part.

New energy vehicles have high requirements on batteries, and must have high specific energy, high specific power, fast charging and deep discharge performance, and require low cost and longest service life. The traditional lead-acid batteries, nickel-cadmium batteries and nickel-hydrogen batteries are relatively mature in their own technology, but they are used as power batteries in automobiles. At present, more and more car manufacturers choose to use lithium batteries as the power battery for new energy vehicles.
Lithium battery has the following advantages: small size, light weight, high working voltage (three times nickel-cadmium battery, hydrogen-nickel battery), large specific energy (up to 165WH/kg, three times that of hydrogen-nickel battery), cycle life Long, self-discharge rate, no memory effect, no pollution, good safety and so on.

1. Development status of power lithium battery
The replacement of traditional gasoline vehicles by new energy vehicles in the future has become the consensus of all countries in developing the automobile industry. The power battery as the core component is more favored by enterprises and investors. Power battery is the key to the development of new energy vehicles: Hybrid vehicles are the best transition products at present, but pure power battery vehicles are the future development direction, and the core technology is a breakthrough in battery technology.
China's new energy car battery industry started later than Europe and the United States, but the development is very fast, and also invested a lot of financial and material resources in the research and development of lithium batteries. The National 863 Program established a major special project for electric vehicles. The Institute of Physics of the Chinese Academy of Sciences, the Beijing Nonferrous Metals Research Institute, and the 18th Research Institute of China Electronics Technology Group Corporation participated in the project, and developed two types of power batteries for EV and HEV. Some of these units have adopted a safe manganese active material. The "Eleventh Five-Year Plan" and 863 electric vehicle major projects have given great support to the research and development of key materials and batteries for power lithium-ion batteries for HEV, PHEV (external plug-in hybrid vehicles) and FCV (fuel cell vehicles).

2. Problems encountered in the development of power lithium batteries
The bottleneck that currently hinders the development of power lithium-ion batteries is: safety performance and management systems for automotive power batteries.
In terms of safety performance, lithium-ion battery has high energy density, high operating temperature and harsh working environment, and people-oriented safety concept. Therefore, users have very high requirements for battery safety. In the management system of the automobile power battery, since the working voltage of the automobile power battery is 12V or 24V, and the operating voltage of the single power lithium ion battery is 3.7V, it is necessary to increase the voltage by connecting a plurality of batteries in series, but it is difficult to implement the battery. Fully uniform charge and discharge, thus causing a single battery in a series of battery packs to be charged and discharged unbalanced, the battery will be undercharged and over-discharged, and this situation will lead to a sharp deterioration of battery performance, and ultimately As a result, the entire battery is not working properly or even discarded, which greatly affects the service life and reliability of the battery.
Power lithium-ion batteries should be well applied, and technically need to consider both materials, batteries, management systems, and machining. Therefore, lithium-ion electronics manufacturers and downstream enterprises are required to work together to take batteries as the core and put forward requirements on materials and management systems to form an industrial cluster, which is more conducive to technological advancement and system cost reduction.

3. Analysis of power lithium battery materials
Lithium battery materials can be divided into electrode (positive/negative) materials, separators and electrolytes. The positive electrode material is the core of the lithium battery, and currently is mainly composed of lithium cobaltate, lithium manganate, nickel cobalt manganese lithium and lithium iron phosphate. The negative electrode material is mainly graphite and solid carbon particles; in the middle of the positive and negative electrodes, the battery electrolyte and the separator.
3.1 cathode material
Previously, the reason why the cost of lithium batteries is higher than that of nickel-metal hydride batteries is that the positive electrode material uses lithium cobaltate, which is made of precious metal cobalt. Lithium manganate and lithium iron phosphate are more obvious due to cost advantages; however, Compared with lithium manganate, the capacity density of lithium iron phosphate is higher, the former is 100-115mAH/g, the latter is 130-140mAH/g; the charge and discharge life is longer, the former is more than 500 times, and the latter is up to 1500 times. Above; the operating temperature range is larger, the former is 0 to 50 ° C, and the latter is -40 to 70 ° C. Therefore, in lithium ion batteries, lithium iron phosphate batteries are the most favored.
In the current capacity comparison of the lithium battery industry chain, due to the high barriers to entry, the production capacity of lithium battery cathode materials is the smallest, which is the most promising link in the entire industry chain.
3.2 Anode material
Compared with the cathode material, the anode material accounts for a lower proportion of the cost of the lithium battery, and has been industrialized in China, and the anode material is mainly graphite and solid carbon particles. At present, the top three enterprises engaged in the production of lithium battery anode materials are China Guoan, Shanshan, and Changsha Hairong. At present, the anode materials can basically meet the needs of the domestic market, but with the gradual popularization of new energy vehicles, this market will be in the future. There will be a huge gap in demand.
3.3 electrolyte
The domestic battery manufacturer's electrolyte package has also been basically localized. The main raw material of the electrolyte is lithium hexafluorophosphate, which accounts for about 50% of the cost of the electrolyte. The production cost is 100,000 yuan/ton, the price is 400,000 yuan/ton, and the gross profit margin is as high as 75%. However, the market is basically Kanto Electric. Chemical companies, SUTERAKEMIFA, Morita Chemical and other Japanese companies monopolize. Therefore, it is urgent to solve the problem of mass production of lithium hexafluorophosphate (LiPF6), the most critical electrolyte component of lithium battery electrolyte. Only this key technology breakthrough, China's automotive power lithium battery industry chain can be close to perfect.
At present, the global supply and demand of lithium battery electrolyte market is basically balanced. Lithium batteries have higher requirements on electrolytes, but the dosage is very small. For example, a mobile phone battery only uses 3 grams, the proportion is very small, 2000 tons of electrolyte can be used to produce 600 million mobile phone batteries. The car's power battery can be different, and a car needs 40 kilograms. Once an electric car rises, it will bring explosive growth of electrolyte.
3.4 diaphragm
With the gradual promotion of new energy vehicles, the demand for power lithium battery materials will be detonated in the future. A high value-added material with the highest technical barrier in diaphragm lithium battery materials, the gross profit margin usually reaches more than 70%, accounting for 20-30% of the cost of lithium batteries. According to calculations, a car can use a diaphragm of one thousand to two thousand square meters. At present, the supply of the diaphragm market is seriously insufficient, and most of them rely on imports. The market is mainly controlled by Asahi Kasei Industrial Co., Ltd., Toho Chemical, and Celgard. The diaphragm has the typical "high technology, high capital" characteristics, and the project cycle is very long, the investment risk is large, and the investment enthusiasm of domestic enterprises is not high.

4. Development prospects of power lithium batteries
According to the "2008-2010 China New Energy Vehicle Industry Analysis and Investment Advisory Report", combined with China's energy resources and the development trend of international automotive technology, it is estimated that by 2012, the annual output of new energy vehicles will reach 1 million vehicles. It is estimated that after 2025, China's ordinary gasoline vehicles will account for only about 50% of passenger cars, and new energy vehicles such as advanced diesel, gas and biofuel vehicles will develop rapidly.
In the future, the trend of replacing new energy vehicles with traditional vehicles will become inevitable. Power lithium batteries, as the "heart" of new energy vehicles, will give birth to huge industrial economic effects, which are huge commercial cakes for battery raw material suppliers and manufacturers.
It is estimated that by 2012, the annual output of new energy vehicles will reach 1 million vehicles, with a cost of 70,000 yuan per new energy vehicle battery, 52 kilograms of positive lithium iron phosphate material for power lithium batteries, 41 kilograms for negative electrode materials, and 40 kilograms of electrolyte. Calculation. One million hybrid vehicles will drive 52,000 tons of cathode materials, 41,000 tons of anode materials and 40,000 tons of electrolytes. For domestic battery manufacturers, this will be a big cake with a total output value of 70 billion yuan. And if calculated by passenger car, this value will be increased by three times - the battery demand of each hybrid bus is four times that of the car.