Tesla made eye-opening again in the past two days. Foreign media reported that Tesla recently provided Tesla Model 3 battery technology details in its shareholder's e-mail, including the current raw material ratios used in its batteries.
Earlier, Musk claimed that the 21700 lithium battery used in Model 3 had an energy density of approximately 300 watt-hour/kg, which is almost the world's highest energy density lithium-ion battery. Tesla set a new world Most of all, we will wait and see.
According to a report on May 14, the US media stated that in the first quarter of 2018, China contributed about half of the total sales of new energy vehicles in the world. Tesla claimed that its newly introduced battery can be fully charged in 20 minutes and last for 350 hours. Kilometers. Does China have such a large market, can it make similar super batteries? The batteries used in new energy vehicles in China are not yet dominating the world, but are they limited to manufacturing materials or key technologies? Or they have chosen different technical routes. ?
Challenge without limits Chasing energy density vs. risk
Tesla claims that the battery cell energy density is up to 300 Wh/kg. The higher the energy density of the battery, the higher the chance of a burning and explosion accident. Zhang Yu, Secretary General, Power Battery Applications Branch, China Chemical and Physical Power Industry Association Said that the battery's core is in the battery management system, although Tesla better solved the problem of thermal runaway caused by the increase of energy density through the battery system management technology, and successfully avoided the short cycle life of the ternary lithium battery through the vehicle design. Difficulties. But if we want to further increase energy density, we will pose greater challenges to battery safety management.
Tesla claimed that the highest energy density of lithium-ion batteries, the eyes of experts in the industry is not perfect.
Yang Yusheng, an academician of the Chinese Academy of Engineering, stressed on many occasions that constantly increasing the specific energy of a battery is a very dangerous path.
Earlier, the China Association for Science and Technology Chairman Wan Gang had publicly stated that from the market point of view, driving mileage is indeed an important symbol of technological advances in electric vehicles, but its realization is not simply to increase the amount of on-board batteries will be able to solve.
The higher the energy density of the battery, the greater the amount of electricity stored in a unit volume. The battery energy density and the loading capacity determine the battery life of the electric vehicle. In the past decade or so, the increase in battery energy density was mainly due to the technical progress of the battery material itself. The proportion of active material in the battery and the increase in the battery to achieve. ' Hefei Guoxuan High Energy Power Co., Ltd. Deputy Director of Engineering Research Institute, Yang Xuan Lai said that by increasing the battery size to reduce the weight of the shell and other auxiliary materials can also reach the battery energy density The effect of promotion.
For the new energy industry, which is responsible for national overtaking missions, the importance of power batteries is self-evident. Many in the industry admit that power batteries are the heart of new energy vehicles, and how far new energy vehicles can go depends mainly on In the power battery.
It is worth noting that according to the “Made in China 2025” power battery development plan: By 2020, domestic battery energy density will reach 300 Wh/kg. Experts believe that China is actively promoting the development of high specific energy batteries, but the safety of batteries The relationship between energy and specific energy is still worth studying.
Although technology is difficult, local companies can also produce
Industry experts said that not only is Tesla's battery system control capability, vehicle design is not what most Chinese car companies can imitate and surpass in the short term. Then, Chinese domestic companies can create strong three-wheeler-like life. Lithium battery?
In the battery's four main materials - cathode material, anode material, electrolyte and separator, the cathode material not only accounts for 40% of the cost, but also directly determines the energy density of the cell. According to the cathode material technology route, the power battery can be mainly Divided into three types of lithium iron phosphate, three yuan lithium (NCA / NCM) and lithium manganate batteries.
According to the structure of the positive electrode material, the ternary lithium battery is divided into two types of NCA and NCM. NCM means that the positive electrode material is made of a combination of nickel, cobalt and manganese materials in a certain proportion, and the positive electrode material of NCA is made of nickel and cobalt aluminum. Sura claimed that the strong battery life is a three yuan lithium NCA battery.
Zhou Bo, director of the research division of the Power Battery Applications Branch of the China Chemical and Physical Power Industry Association, said that NCA's production process conditions are more stringent and that there are barriers to the manufacturing process. More importantly, NCA's technical barriers are also high, and current production capacity is mainly concentrated in Japan, South Korea, China produces less.
'The NCA battery can also be done in China. Last year, a key domestic material company supplied more than 1,000 tons of Panasonic to Japan.' said Zhang Yu.
However, according to the reporter’s understanding, the industrial development of domestic NCA materials and their batteries started relatively late. At present, many companies have started pilot tests and trial production in small batches. There are also some technical problems that need to be solved, and no mass production and sales have been formed. , Limited production materials, foreign NCA material market mainly Sumitomo Metal, Japan Chemical Industry Co., Ltd. monopoly.
Zhang Yu analyzed that the reason behind the failure of mass production of NCA batteries in China is that due to poor thermal stability leading to a decrease in battery safety, battery manufacturers and end product users are concerned about the safety of NCA batteries. This requires reliable design of the system from battery design, power system design, and power supply use. From a processing perspective, NCA batteries require a pure oxygen environment, high processing costs, and humidity control throughout the battery production process. Below 10%, these have great challenges for domestic companies.
Based on the factors of technology, cost and subsidy, China mainly chose the NCM route, but this does not mean that there is no new opportunity for the NCA route.
Cost impact on the market Tesla is not necessarily a benchmark
Although Chinese domestic companies do not make ternary lithium batteries, Tesla's ternary lithium batteries that are challenging the limits are not necessarily the only targets for research and production of new energy vehicle batteries in China.
According to data from the Power Battery Application Branch of China Chemical and Physical Power Industry Association, from January to December 2017, the installed capacity of Sanyuan lithium batteries was 16.04 GWh, accounting for 44.01% of the total; The installed capacity of iron-lithium batteries was 17.97 gigawatt-hours, accounting for 49.29%; the capacity of lithium-manganese batteries was 1.48 gigawatt-hours, accounting for 4.06%...
Industry insiders told the reporter of Science and Technology Daily that under the leadership of the national policy and the blessing of the market environment, China's lithium battery technology line is equal to that of lithium iron phosphate and ternary lithium battery. However, even in the development of the technical route of Sanyuan lithium battery, the domestic power battery The manufacturer's choices are also focused on selecting NCM lineups, and there are very few who choose Tesla to use the NCA route.
NCA batteries have been large-scale, mass-produced, and commercially proven; and high-energy-density NCM batteries have not yet been mass-produced. Industry experts say that the performance of the two is relatively close, but the high energy density of NCM The price is slightly cheaper. Therefore, NCM is more in line with China's market in terms of cost performance.
'In a sense, it is actually lithium iron phosphate that has made China a new energy vehicle. From the cost point of view, lithium iron phosphate is even more dominant. We predict that the future market for lithium iron phosphate batteries should be more than that of three yuan lithium batteries. Da. 'Yang continued to tell the reporter of the Science and Technology Daily that the current trend of the development of ternary lithium batteries, thanks to the requirements of the national policy oriented high specific energy batteries, requires a high battery energy density, long mileage, of course, ternary lithium battery has The higher specific energy and specific power are more in line with the demand of passenger cars, but in the future it may not necessarily be the mainstream of the market.
