300 watt/kg Chinese power cells are close to application requirements

The special research on the special power battery of new energy vehicles of the Ministry of Science and Technology has made substantial breakthroughs. The 300 watt-hour/kg power battery to be industrialized in 2020 is close to the application requirements. Among the three teams, the Ningde era energy density reached 304 watt-hours/kg, the cycle life was basically 1000 times, and the safety was all passed. In addition, the team of lishen and Guoxuan had similar cycle life and energy density.

On January 7, the 100-member China Electric Vehicle Association held a discussion with some media on the China 100 Electric Vehicle Association Forum (2018). Ou Yangming, executive vice president of China electric car 100-person Association, spoke of the progress. Ou yangming is also the leader of the overall expert group of the National 863 plan "Energy Conservation and New Energy Vehicles".

Ou yangming introduced that the three teams adopted similar technical routes, are very high nickel three yuan, negative pole is Silicon negative. It's basically a soft-pack battery, not a square battery.

Ou yangming explained that a 300 watt/kg monomer can probably make a 200-210 watt/kg battery system. At the end of 2017 and early 2018, the level of the industry was: the energy density monomer was about 230 watt/kg, and the system was about 150 watt/kg. "It means that we need to increase 50 to 70 watts/kg in 2018 and 2019. I think it can be done. As for(power core) 350 watt/kg,(system) 260 W/kg is our goal. "

Ou yangming also described the status and goals of two other power cell studies.

One is the 2025 industrialization, which hopes to impact a single battery 400 watt/kg power battery. He said that 300 watts/kg of power cells required a negative electrode to change from carbon to Silicon. 400 watt/kg power battery, to change is the positive pole. "At present, there are several types of positive poles that can be selected. Now, we have made breakthroughs in our new energy vehicles. The high-capacity lithium-rich manganese base positive polar materials have been made. Two units have undertaken frontier basic projects: one is the [Chinese Academy of Sciences] Institute of Physics. The improvement of voltage attenuation of lithium-rich manganese base positive cycle, the target achieved is that after 100 weeks the voltage attenuation has dropped to within 2 %, which should be said to be a major progress. Another is the team of Peking University. For the first time, it has developed a lithium-rich manganese base positive pole with a capacity of 400 mA / g. For 400 watt/kg, it should be no problem or even higher. "

The second is solid batteries. "Solid state batteries have a number of research institutions and industrial units in China, including the Qingdao Energy Institute of the Chinese Academy of Sciences, the Ningbo Institute of Materials (Chinese Academy of Sciences), the Institute of Physics(Chinese Academy of Sciences), etc., as well as new energy sources in the Ningde era and China Airlines Lithium. Recently, Ningbo Materials Institute cooperated with the Lithium industry and is promoting industrialization and planning mass production in 2019. "

Looking at the current status of China's power battery research in 2017, Ou yangming gave the following summary:

First, lithium-ion power batteries are expected to achieve the target of 300 watt/kg by 2020. At present, domestic and foreign technology research and development are basically at the same level, but safety research has yet to be strengthened.

Second, as two new types of systems to achieve long-term goals, lithium-sulfur and lithium-air batteries are currently making slow progress at home and abroad. In 2017, no breakthrough progress was seen.

Third, the industrialization of research and development of solid state batteries continues to heat up, but it is constrained by two major problems: the stability of the solid / solid interface and the recharging of lithium metal negative poles. The true all-solid lithium metal negative battery has not yet matured. However, lithium ion batteries with inorganic sulfides as solid electrolytes have made breakthroughs.

Fourth, China has made some breakthroughs in high-capacity lithium-rich positive electrode materials in 2017. An innovative lithium ion battery based on high-capacity lithium-rich positive electrode and high-capacity Silicon negative electrode is more feasible than lithium sulfur and lithium empty battery.

As a result, the overall expert group of the "Energy Conservation and New Energy Vehicles" major projects updated the judgment of the development trend of power battery technology:

In 2020, the power battery will achieve a specific energy of 300 watt/kg, a specific power of 1,000 watt/kg, a cycle of more than 1,000 times, and a cost of 0.8 yuan/watt-hour. "This is certain." The corresponding material is high nickel ternary. "The ratio of nickel, cobalt, and manganese is changed from 3:3:3 to 6:2:2, which is high nickel, nickel becomes 6, and then it is converted to 8:1:1, nickel becomes 8, and cobalt is further reduced to 1, Even cobalt was further reduced to 0.5. The negative electrode should be transformed from a carbon negative electrode to a Silicon negative electrode. This is our current technological change. "

By 2025, the cathode material will further improve its performance, such as lithium-rich manganese-based materials. "From 2020 to 2025, the power density of the power battery is 400 watt-hours/kg from 300 watt-hours/kg, and the cost per watt-hour is less than 8 cents to less than 6 cents. At this time, our general price-performance pure electric car A reasonable mileage of 300-400 kilometers."

By 2030, "we hope to make breakthroughs in electrolytes, that is, the biggest breakthrough from 2025 to 2030 may be in electrolytes, that is, the scale of solid batteries will be industrialized, and the battery monomer ratio is expected to impact 500 watts/kg". In 2030, conventional cost-effective models should reach more than 500 kilometers.

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