Earlier, Musk claimed that the energy density of the 21700 lithium battery first used in Model 3 is close to 300 Wh/kg, which is almost the highest energy density mass-produced lithium-ion battery in the world. Whether Tesla has set another world record, we will wait and see.

　　Challenge unlimited chasing energy density is more risky

　　"Tesla claims that the energy density of battery cells is up to 300 watt-hours/kg. The higher the battery energy density, the higher the probability of a combustion and explosion accident." Zhang Yu, Secretary-General of the Power Battery Application Branch of the China Chemical and Physical Power Industry Association Said that the core of the battery is the battery management system, although Tesla has better solved the thermal runaway problem caused by the increase in energy density through the battery system management technology, and successfully avoided the short cycle life of the ternary lithium battery through the car design. problem. However, if the energy density is to be further improved, greater challenges will be presented to battery safety management.

　　The lithium-ion battery with the highest energy density claimed by Tesla is not perfect in the eyes of industry experts.

　　Yang Yusheng, academician of the Chinese Academy of Engineering, emphasized on many occasions that continuously increasing the specific energy of batteries is a very dangerous way.

　　Previously, Wan Gang, Chairman of the China Association for Science and Technology, publicly stated that from the market perspective, the driving range is indeed an important sign of the technological progress of electric vehicles, but its realization cannot be solved by simply increasing the amount of on-board batteries.

　　"The greater the energy density of the battery, the greater the amount of electricity stored per unit volume. The energy density and load capacity of the battery determine the endurance of electric vehicles. In the past ten years, the increase in battery energy density has mainly relied on the technological progress of the battery material itself. And increase the proportion of active substances in the battery." Yang Xulai, vice president of the Engineering Research Institute of Guoxuan High-tech Power Energy Co., Ltd., said that by increasing the size of the battery and reducing the weight of auxiliary materials such as the casing, the energy density of the battery can also be improved. Effect.

　　For the new energy industry that is responsible for the national curve overtaking mission, the importance of power batteries is self-evident. Many people in the industry admit that power batteries are the heart of new energy vehicles, and how far a new energy vehicle can go depends mainly on power batteries.

　　It is worth noting that according to the "Made in China 2025" power battery development plan: By 2020, the energy density of domestic batteries will reach 300 Wh/kg. Experts believe that my country is actively promoting the development of high specific energy batteries, but the relationship between battery safety and specific energy is still worth studying.

　　Local companies can produce even if there are technical problems

　　Industry experts said that not only Tesla’s battery system control capabilities, but also the vehicle design is not something that most Chinese car companies can imitate and surpass in the short term. So, can local Chinese companies create ternary lithium batteries that have the same battery life as Tesla?

　　In the four main materials of the battery-positive electrode material, negative electrode material, electrolyte and separator, the positive electrode material not only accounts for 40% of the cost, but also directly determines the energy density of the battery. According to the technical route of the cathode material, power batteries can be mainly divided into three types: lithium iron phosphate, ternary lithium (NCA/NCM) and lithium manganate batteries.

　　According to the composition of the cathode material, ternary lithium batteries are divided into NCA and NCM. NCM means that the positive electrode material is composed of three materials of nickel, cobalt and manganese in a certain proportion, while the positive electrode material of NCA is composed of nickel, cobalt and aluminum. The strong battery life claimed by Tesla this time belongs to the ternary lithium NCA battery.

　　Zhou Bo, director of the Research Department of the Power Battery Application Branch of the China Chemical and Physical Power Supply Industry Association, said that the production process conditions of NCA are more demanding, and there are barriers to the production process. More importantly, the technical barriers of NCA materials are also very high. At present, production capacity is mainly concentrated in Japan and South Korea, while mass production in my country is relatively small.

　　"NCA batteries can also be made in China. Last year, a key domestic material company supplied more than 1,000 tons of Panasonic." Zhang Yu said.

　　However, according to the reporter's understanding, the industrial development of domestic NCA materials and batteries started late. At present, many companies have started pilot trials and small batch trials. There are still some technical problems that need to be resolved, and mass production and sales have not been formed. At the same time, production materials are limited, and the foreign NCA material market is mainly monopolized by Sumitomo Metals and Japan Chemical Industry Co., Ltd.

　　Zhang Yu analyzed that the deep-seated reason why NCA batteries have not been mass-produced in China is that the safety of batteries has declined due to poor thermal stability, and battery manufacturers and end product users have concerns about the safety of NCA batteries. This requires reliable and safe design of the system from cell design, power supply system design, and power supply use. From a processing perspective, NCA batteries require a pure oxygen environment and high processing costs. The humidity must be controlled below 10% during the entire battery production process, which poses great challenges to domestic enterprises.

　　Based on the factors of technology, cost and subsidies, China mainly chose the NCM route, but this does not mean that there are no new opportunities for the NCA route.

　　Cost affects the market Tesla may not be the benchmark

　　Although local Chinese companies are not unable to produce ternary lithium batteries, Tesla's challenge to the limit of ternary lithium batteries is not necessarily the only goal of my country's new energy vehicle battery research and production.

　　According to data from the Power Battery Application Branch of China Chemical and Physical Power Supply Industry Association, from the perspective of different battery material types, the installed capacity of ternary lithium batteries from January to December 2017 was 16.04 gigawatt-hours, accounting for 44. 01%; the installed capacity of lithium iron phosphate batteries is 17.97 gigawatt-hours, accounting for 49.29%; the installed capacity of lithium manganate batteries is 1.48 gigawatt-hours, accounting for 4.06%...

　　Industry insiders told reporters that under the guidance of national policies and the blessing of the market environment, my country’s lithium battery technology route is both lithium iron phosphate and ternary lithium batteries. However, even in the development of the technical route of the ternary lithium battery, the choice of domestic power battery manufacturers is also focused. There are many people who choose the NCM route, and few choose the NCA route used by Tesla.

　　NCA batteries have been mass-produced on a large scale and mature, and have been commercially verified; while high-energy-density NCM batteries have not yet been mass-produced. Industry experts said that the performance of the two is relatively close, but the price of the high energy density NCM is slightly cheaper. Therefore, in terms of cost performance, NCM is more in line with the Chinese market.

　　"In a sense, it is actually lithium iron phosphate that has made China's new energy vehicles. From a cost perspective, lithium iron phosphate is more dominant. We predict that the market for lithium iron phosphate batteries in the future should be more than that of ternary lithium batteries. Big.” The current development trend of ternary lithium batteries benefited from the national policy-oriented requirements for high specific energy batteries, which require batteries with high energy density and long cruising range. Of course, the ternary lithium battery has a higher specific energy and specific power, which is more in line with the needs of passenger cars, but it may not necessarily be the mainstream of the market in the future.