The theoretical energy density of lithium iron phosphate battery is only 180Wh/kg, and the ternary material battery has taken up the heavy responsibility. The ternary material system is numerous, which is the correct route? After many companies continue to explore, everyone seems to reach a consensus. The ternary material battery of high nickel system is the future development direction.
Recently, the Ministry of Industry and Information Technology released the sixth batch of "Recommended Models for the Promotion and Application of New Energy Vehicles" in 2018 (referred to as "Recommended Catalogue"). According to the new energy vehicle subsidy new policy requirements, starting from June 12, starting from the fifth batch of this year, In the 5th batch, the 6th batch of "Recommended Catalogue" puts higher requirements on the battery energy density and driving range of the car.
In fact, the “Promoting Action Plan for Promoting the Development of Automotive Power Battery Industry” has already clarified the goal of China's power battery. By 2020, the specific energy of lithium-ion power battery cells is greater than 300Wh/kg; the system specific energy is expected to reach 260Wh/kg; Less than 1 yuan / Wh; use environment from minus 30 ° C to 55 ° C; with 3C charging capacity, and strive to achieve a single battery 350Wh / kg.
The theoretical energy density of lithium iron phosphate battery is only 180Wh/kg, and the ternary material battery has taken up the heavy responsibility. The ternary material system is numerous, which is the correct route? After many companies continue to explore, everyone seems to reach a consensus. The ternary material battery of high nickel system is the future development direction.
■High-nickel ternary materials become mainstream
Economists often use the two curves of supply and demand to analyze the market. The intersection of the two is the balance point. Power battery companies also apply this principle to analyze product development trends.
Wu Kai, vice president and chief scientist of Ningde Times New Energy Technology Co., Ltd., demonstrated the relationship between power battery energy density and cost. As the scale expands, technology advances, the cost curve slopes downwards; the way to overcome 'mileage anxiety' is only Increasing energy density is also the direction encouraged by the Chinese government and industry. The upward energy density curve forms an intersection with the cost curve, and the power battery companies revolve around this.
Wu Kai said: 'The design of the battery is based on the balance between cost and energy density. Under the equilibrium point, the ternary material has an advantage; above the equilibrium point, the silicon-based anode system and the solid-state battery have an advantage. In the context that solid-state batteries are not yet commercialized, the ternary material system has become the main target.
Recently, at various industry development forums, experts from enterprises and scientific research institutions have mentioned that lithium iron phosphate batteries are limited by their own material properties, and it is difficult to meet the national energy density requirements by 2020 at the current technical level. The same is true for types of batteries such as NCM111 and NCM523 in the metamaterial.
According to experts, the current NCM523 battery has an energy density of 160~200Wh/kg, which is a large distance from 300Wh/kg. Researchers improve the nickel content in the ternary system, and the energy density of the battery is significantly improved. NCM622 and NCM811 It reaches 230Wh/kg and 280Wh/kg respectively. In order to reach the target of 300Wh/kg, high-nickel ternary materials have become an inevitable choice.
The data shows that in the first quarter of 2018, the domestic ternary material output was 31,670 tons, a year-on-year increase of 64.26%. Among them, the conventional NCM model accounted for 78%, the NCM622 model accounted for 14%, the NCM811/NCA accounted for 8%, and the NCM811 output increased significantly. .
At present, there are two routes for high-nickel ternary materials, NCM (nickel-cobalt-manganese) and NCA (nickel-cobalt-aluminum). In high-nickel ternary materials, the main role of nickel is to provide capacity, the higher the content, the battery The higher the energy density; the cobalt element plays a role in stabilizing the structure while contributing a part of the capacity; manganese/aluminum is mainly used to stabilize the ternary system structure.
■Enterprises are at the forefront with technology accumulation
BAK is an enterprise engaged in R&D and production of ternary batteries earlier in the country. It has accumulated rich experience since 2006. At present, BAK has realized the bulk supply of NCM811 power battery.
The ternary batteries produced by BAK are all cylindrical batteries. At present, they mainly supply 18650-2.75Ah batteries. The reporter saw the zero-run LP-S01 electric car equipped with 18650-2.75Ah batteries in the BAK battery factory. Introduction, its total package power is 36kWh, the maximum driving range is 360km, and the driving range is 250km under NEDC conditions. It can be filled in 8~10 hours in slow charging mode and 80% in 48 minutes in fast charging mode. In extreme emergency Charging in mode for 10 minutes can drive 60km.
In May of this year, BAK 3.0Ah battery products were launched, and the energy density reached 250Wh/kg, which helped the new energy vehicles to achieve long battery life. BAK's ternary material battery is no longer only 18650 batteries, 21700 batteries have been completed many times. Downline internal testing, 4.8Ah 21700 cylindrical battery began small batch samples, is expected to achieve large-volume shipments in the fourth quarter of this year, the end of the year launched 5.0Ah products.
Tianjin Lishen has formed its own characteristics in the development of ternary materials. Based on the research of NCA cathode materials, it develops high-nickel cathode materials for lithium-ion power batteries with high specific energy, long cycle life and good safety performance, and Preparation, nano-dispersion, coating and pre-intercalation of lithium and other technologies, high research and development capacity, high efficiency, high cycle stability and rate performance of silicon carbon anode materials.
The breakthrough in R&D technology of positive and negative materials has enabled the energy density of Tianjin Lishen ternary material battery to reach the national design goal ahead of time. It is reported that the specific energy of cell core developed by it is 302Wh/kg, and the volumetric energy density is greater than 642Wh/L. 1C charge and discharge cycle at 1500°C (100% DOD) at 25°C, the capacity retention rate reached 80%. Tianjin Lishen improved the cycle performance by further optimizing the electrolyte formulation, and currently 285 cycles (100% DOD) capacity retention rate Up to 96%. This laid the foundation for the development of a lithium-ion battery cell with a specific energy of 300Wh/kg and a cycle life of 1500 cycles.
■Ternary material pain points to be broken
The advantages of ternary materials are obvious, and the pain points are also very prominent. First, the technical difficulty is large. Second, the increase in material prices restricts the cost reduction. Japan's Panasonic battery is the first to achieve high-volume ternary material battery production, and only a few companies in China mass production. NCM811, the technical difficulty can be imagined. Luo Zhaojun said: 'High nickel materials are not only high alkalinity, but also oxidative problems. These two technical challenges have become the 'blocking tiger' for many companies to develop high-nickel ternary materials. Years of ternary battery research and development experience, experience has played an important role in solving the problem. 'Accordingly, Bick through the study of material thermal characteristics and stable film-forming additives, ceramic diaphragm technology applications and structural parts optimization and other aspects Completed multi-layered security guarantee.
Metallic cobalt must be used in the ternary material system. China is a country with poor cobalt resources and must rely on imports. In recent years, as the global new energy vehicle promotion boom has heated up, cobalt prices have continued to rise. In 2015, the global supply of refined cobalt was about 10.2 million tons, and the demand for cobalt is about 92,000 tons. The price of cobalt remains relatively balanced. In 2016, the price of cobalt began to rise steadily, but the speed was not fast, and it remained between 100,000 and 150,000 yuan/ton. The price of cobalt began to rise all the way. According to some data, in 2018, the price of cobalt may reach 800,000 yuan / ton.
An industrial investor who asked not to be named told the China Auto News reporter that the scarcity of metallic cobalt, tight supply and demand, oligarchy control, small varieties are easy to be speculated in the futures market, and the Congo (Golden) situation and other factors have become The price of cobalt continues to be the source of power.
In the context of the new energy vehicle subsidies and the implementation of the 'double points' policy, in order to increase market competitiveness, auto companies require battery companies to reduce supply prices every year. The “requests” of price by automakers are becoming more and more fierce. 3. The ternary material's ability to cut prices is limited, and high cost has become a headache.
In order to cope with the cost troubles, battery companies try to further adopt the high nickel method. It is understood that some domestic enterprises are studying 9:0.5:0.5 ternary material batteries, increasing the use of nickel, reducing the amount of cobalt, thereby avoiding the rising price of cobalt. The cost is troubled.
As the world's leading ternary material battery company, Panasonic Japan has gone further on the high-nickel road. Not long ago, Kenji Tamura, head of Panasonic's automotive battery business, said in a meeting with analysts: 'We have significantly reduced cobalt The amount of use, and hope to achieve cobalt-free batteries in the near future, the current research and development is already underway.'
