21700 battery

How to break through the technical threshold when high nickel content in power 21700 battery is becoming a trend?

The current power battery industry is playing out a "Three Kingdoms" situation between China, Japan and South Korea. In the early days, China's battery industry has made great progress due to policy dividends and subsidy advantages, and my country has become the country with the largest power battery shipments in the world. CATL, BYD and others have risen rapidly, and are not much different from foreign-funded enterprises in terms of technology, but objectively speaking, my country's overall battery industry still does not have the ability to fully compete with Japan and South Korea.

Recently, a piece of news has caused a new topic in the battery industry. It is reported that CATL is expected to launch a new battery using NCM811 (nickel-cobalt-manganese ternary lithium) technology next year. If this plan is successfully implemented, it will have an important impact on the power battery industry in China and even the world.

According to the requirements of the "Medium- and Long-Term Development Plan for the Automobile Industry" of the Ministry of Industry and Information Technology, by 2020, the specific energy of new energy automobile power batteries will reach more than 300Wh/kg, and strive to achieve 350Wh/kg, and the system specific energy will strive to reach 260Wh/kg, and the cost will be reduced to less than 1 yuan/Wh. By 2025, new energy vehicles will account for more than 20% of automobile production and sales, and the specific energy of power battery systems will reach 350Wh/kg.

The current mainstream NCM523 battery can reach 160-200Wh/kg, while NCM622 and NCM811 can reach 230Wh/kg and 280Wh/kg respectively. Therefore, in order to achieve the planned requirements for power battery energy density and cruising range, vigorously developing NCM811 batteries has become an inevitable trend.

The cost pressure caused by rising cobalt prices is a "catalyst"

The rising prices of upstream raw materials have put great pressure on battery manufacturers, and the rising prices of cobalt, a raw material for the positive electrode, have brought the greatest cost pressure. In order to alleviate cost pressure, domestic mainstream battery companies have basically chosen to reduce the proportion of cobalt use through innovation of ternary positive electrode materials.

Public information shows that BYD, CATL, Guoxuan High-tech, Shanshan Energy, etc. have all started to deploy in the field of high-nickel 811 batteries. By increasing the proportion of nickel, increasing the energy density of the battery, and reducing the use of cobalt, the cost pressure brought by the rising price of ternary materials has been resisted in terms of cost.

BYD has previously stated that it expects to start using ternary high-nickel 811 batteries in the second half of 2019. At the beginning of this year, Guoxuan High-tech said that it has developed a ternary 811 material soft-pack battery cell with an energy density of 302wh/kg, and it is expected to be produced and supplied in small batches in 2019.

Chinese companies have little say in high-nickel batteries, and it will take some time for commercialization to be popularized

Although the 811 ternary system material is sought after by the industry, the road to commercialization caused by its technical shortcomings is also a realistic problem.

Technically, the nickel element has unstable characteristics, and the production and manufacturing process of high-nickel batteries is prone to adverse reactions such as weakened cycle performance, reduced safety performance, and reduced charging efficiency. The storage and production process are more difficult. High-nickel ternary materials are prone to moisture absorption and jelly-like during storage and use, and are not easy to mix slurry and electrode coating, and the performance requirements of production equipment are very high.

In addition, high-nickel materials must be synthesized in a pure oxygen environment and lithium hydroxide must be used as a lithium source for high-temperature synthesis. Therefore, the kiln materials used by cathode material companies must be resistant to oxygen corrosion and alkali corrosion, but domestic preparation technologies rarely meet the standards. Even if the equipment meets the standards, high-nickel 811 power batteries still have problems including thermal management systems and supply system reshaping that need to be solved.

Chinese companies do not have a high voice in the field of high-nickel ternary power batteries. Currently, Panasonic is the best in commercialization in this field. Its 21700 cylindrical battery used in Tesla Model 3 has achieved a 20% increase in battery energy density by improving the application of high-nickel cathode materials and silicon-carbon anode materials.

In addition to Panasonic, South Korean lithium battery giants LG Chem, SKI, and Samsung SDI are also actively preparing for high-nickel 811 batteries. The KonaEV pure electric SUV released by Hyundai previously uses NCM811 cells provided by LG Chem.

Another Korean battery company, SKI, also announced last year that it had begun mass production of NCM811 batteries for energy storage systems and would provide batteries for electric vehicles in the third quarter of 2018.

Samsung SDI's main strategic cooperation is with BMW. According to BMW's plan, i3 will not use NCM622 until 2018 and NCM811 products until 2012, which is relatively conservative.

The latest news is that LG Chem and SKIN's CM811 battery plan has been delayed. Although it cannot be supplied to car companies in large quantities at the mass commercialization level, the technical reserves of the two companies should not be underestimated. Back to domestic companies, the current power batteries for new energy vehicles under CATL are mainly NCM523 batteries. To jump directly from NCM523 to NCM811, CATL still needs to overcome many problems.

In the long run, if we want to meet the energy density development requirements of power batteries in 2020 and beyond, the existing liquid electrolyte battery system may be powerless. Solid-state 21700 battery are expected to become the dominant technology route for the next generation of automotive power batteries.

Since electrolyte and diaphragm are not needed, but replaced by solid electrolyte, the thickness of solid-state battery will be smaller at the same energy density. In terms of weight, after using solid electrolyte, graphite negative electrode can be replaced by metal lithium to reduce the amount of negative electrode material, which significantly reduces the weight of the whole battery. At the same time, higher safety and better fast charging capability are also its advantages over current lithium-ion batteries. When integrated into electric vehicles, solid-state batteries also have the characteristics of compact structure, adjustable scale, and large design flexibility, which are conducive to vehicle integration.

In general, the reduction of material costs and the improvement of battery performance in recent years are the driving forces for the development of NCM811, but due to the pressure of technical challenges, it will take some time for NCM811 to truly achieve commercial application. At this stage, Chinese battery companies still need to step by step to cross the technical threshold.

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