From electric cars included in the national 863 high-tech development, to the new energy automotive industry listed in the state of seven strategic emerging industries, from the four ministries and commissions of the state in 2009 began to perform two rounds of new energy car subsidy policy, China's new energy automotive industry for nearly 10 years obtained the rapid development, but the development of new energy automobile power lithium batteries in China has always been controversial: direction The dispute of lithium manganate, lithium ternary, lithium iron phosphate has not subsided.
Regardless of the complex technical superiority debate, as long as we understand what the key factors and supporting points are for China's new energy vehicle industry to achieve rapid development and really achieve curve overtaking, then, the direction selection of new energy vehicle power lithium-ion battery should not be a complex issue.
In fact, these key factors and supporting points, the industry has already formed a consensus: first, the development of China's new energy vehicles, must ensure the use of safe and reliable, stable performance and low-cost power lithium batteries, among them, safety and reliability is the first, no safety will not have the future of the new energy vehicle industry; Second, in technology should be able to surpass and lead developed countries and regions, rather than always in a state of catch-up, only in this way, China's new energy vehicle industry can truly achieve the curve overtaking.
The key factors and support for the development of new energy vehicles in China are clarified. According to the actual situation of our industry, the current situation and development direction of ternary and lithium iron phosphate are compared.
First, if we continue to develop three yuan, our power lithium ion battery will always be in a state of catch-up, not only can not achieve the corner overtaking, but also will lose the safety of new energy vehicles.
At present, the core technology of modified lithium manganate and ternary lithium is in the hands of Japanese and Korean companies. Especially ternary lithium, whether technology, process or equipment, Japan and Korea industry leaders have reached a very mature and stable stage.
At present, Sanyo, Panasonic and Samsung SDI's 18650 ternary lithium ion battery, capacity has done more than 3.1Ah, and the most famous ternary lithium ion battery company's 18650 battery, capacity but also do about 2.2Ah. The 18650 ternary lithium-ion battery mass produced by Sanyo, Panasonic and Samsung SDI has a consistency of more than 90% in several key battery indicators such as voltage, capacity, internal resistance, discharge platform, constant current ratio, etc. It can be formed into a group without capacity distribution, which is also impossible for the excellent ternary lithium-ion battery production companies in China.
If the development direction of China's new energy vehicle power lithium battery is positioned at the development of ternary lithium battery, it is not only in the state of catching up with Japanese and Korean companies for a long time, but also has fallen into a development bottleneck due to the lack of key technologies, processes and equipment.
Taking capacity improvement as an example, the domestic excellent 18650 type lithium ion battery with a capacity of about 2.2Ah has been constantly faced with safety problems. If there is no major breakthrough in technology and process, only material modification or improvement of the electrode compaction density to improve the capacity will not only significantly reduce the cycle performance of the battery, but also, more seriously, The safety problem of ternary lithium battery will be more prominent.
Safe use is the first of the three key elements in the development of new energy vehicles. Tesla uses Panasonic batteries, the best in a three-way lithium-ion battery, which can't prevent three fires in five weeks. Fortunately, Tesla's advanced vehicle safety design did not cause human casualties, and China's new energy vehicle companies in terms of vehicle safety design, and how many can reach the level of Tesla?
The technology is at the hands of Japanese and Korean firms and is far smaller than their giants. Samsung SDI cut the price of the 18650-2.2Ah battery to $1 a battery in a one-off move this year, almost driving its domestic rivals to the wall.
In the domestic three yuan power lithium battery performance and price can not compare with the Japanese and Korean giants, if we adhere to the new energy vehicle lithium battery line, I am afraid we are still catching up on the road, will have been killed by the international giants, not to mention what the curve overtaking. The final result will be the same as the development of traditional cars. High-end cars and core technologies will still come from international giants. Even if we give up the market, we will not be able to get the core technologies back.
Lithium-ion iron phosphate batteries are different. Japanese and Korean companies are largely absent, and major international competitors are from the United States. Although one of the two basic patents is in the United States (A123 and Valence are the important representatives of lithium iron phosphate batteries in the United States), there is not much difference in the technical level between China and the United States. Moreover, China has the largest investment and production and sales volume in the field of lithium iron phosphate in the world.
With the acquisition of A123 by Wanxiang Group, the Chinese company has in fact mastered the world's most advanced technology and process for lithium-ion iron phosphate batteries. The absolute advantage of lithium ion iron phosphate battery on ternary lithium battery in terms of safety and cycle life is exactly the key element of China's new energy vehicles and the need for development. As long as it is clear about its development status and increase investment to solidify this advantage, China's new energy vehicles will completely have the possibility of overtaking on corners.
Second, the choice of ternary, the top design is not forward-looking, the global nickel and cobalt resources are limited, a large number of its application will lead to a sharp rise in the market price, especially the storage of these two elements in China can not support.
The material formula of ternary lithium battery, whether it is lithium nickel-cobalt manganate, or lithium nickel-cobalt aluminate, is inseparable from two precious metals, namely cobalt and nickel. Both metals are scarce in China and have limited global reserves. Among them, China's use of more than 90% of cobalt to import, nickel is important for stainless steel production, these two precious metals are international futures trading, prices are not only high but also fluctuate greatly.
If China determines the lithium battery development route with ternary lithium battery as the important power, according to the government planning, by 2020, the production of new energy vehicles will reach 2 million, and the number of new energy vehicles will reach 5 million. According to the average power of each new energy vehicle lithium battery with 80kWh calculation, 5 million new energy vehicles need 400 billion Wh battery, which does not include the replacement and standby batteries. Once this demand is put on the market, it will soon drive cobalt and nickel futures prices to skyrocket, which will drive the spot market price skyrocket, and the future price trend of Sanyuan lithium will rise straight.
A big reason why the promotion of new energy vehicles in China has not reached the expected goal of the policy is that the price remains high. Among them, the most important reason is the high price of power lithium-ion batteries, which account for nearly 50% of the cost of new energy vehicles. The result of the Sanyuan route is that the price of new energy vehicles will be higher, and the government will require more subsidies, which will never be promoted in the market.
Lithium-ion iron phosphate battery is just the opposite, does not contain any precious metals, and the production of cathode materials of important raw materials iron oxide, lithium carbonate reserves in China is very rich. If the downstream market demand for new energy vehicles is enlarged, the cost of upstream materials will plummet under the impetus of scale effect. The decline in the price of cathode materials, which accounts for more than 30% of the cost of lithium-ion iron phosphate batteries, will promote the rapid decline in the price of lithium-ion iron phosphate batteries.
3. In terms of vehicle safety design, China's new energy vehicles use ternary lithium battery as power lithium battery, which will have huge safety risks.
Of the Tesla's three fires, one of which was caused by a metal strip tearing through the battery, the cars were well designed to catch fire, and no one was injured. The deoxidation temperature of ternary material is 200℃, and the heat release energy is more than 800J/g. The ternary lithium battery can not pass the acupuncture test, which shows that the ternary battery is easy to cause safety accidents in the case of internal short circuit.
At present, the safety design of new energy vehicles in China cannot reach the level of Tesla in a short time, and there are huge safety risks in using ternary lithium battery as the lithium battery for new energy vehicles. Concerning the safety of passengers' lives, this security hazard is unacceptable even if it is one in 100,000 probability.
The stability of lithium-ion iron phosphate battery at high temperature can reach more than 390℃, which ensures the high safety of the battery. It will not explode or burn due to overcharge, high temperature, short circuit, impact, and can easily pass the needle test. This safety feature is the most appropriate for China's new energy vehicle industry, which is still in its infancy.
IV. From the perspective of consumption characteristics and habits of new energy vehicle users in China, ternary lithium battery is not suitable for China's new energy vehicle power lithium battery.
Tesla is known as the rich man's toy. The designed range of battery assembly is 400KM, but most of the time, the actual operation is only about 200KM, which is shallow charge and shallow discharge, so the cycle life is guaranteed. However, China's new energy vehicles are mostly used in public transport, government service, special vehicles and residential passenger cars. Their use features are that most of the fixed lines and frequency requirements are required every day, and they are deep charging and deep discharging. Under the condition of DOD95% or more, the capacity of ternary lithium battery is fast, and the cycle life is only less than half of that of lithium iron phosphate battery.
The average service life of new energy vehicles is more than 8 years. If the power lithium-ion battery is in the condition of deep charging and deep discharging and maintains more than 80% capacity, the service life of ternary lithium battery will be less than three years, while the lithium-ion iron phosphate battery can basically meet the service requirements of 8 years.
Under the current conditions of relevant national subsidy policies, the government will provide corresponding subsidies for the first purchase of new energy vehicles, but there is no subsidy for the second purchase of batteries. The ternary lithium ion battery needs to be replaced twice in the life cycle of new energy vehicles, which will greatly increase the economic burden of users, but will not be accepted by end users.
If ternary lithium electricity to obtain the same service life as lithium iron phosphate, it can only be shallow charge shallow release, need to add at least 50% more than the battery capacity. In this way, the advantage of higher energy density will be lost, and the battery will be larger and heavier than the same performance lithium-ion iron phosphate battery, which will be much more expensive.
In May 2011, the Volt, the most classic hybrid electric vehicle of General Motors, was fitted with a lithium ion battery made by LG Chem of South Korea, and underwent a crash test in the United States. Smokey smoke and open fire occurred in the second test, and spontaneous combustion occurred seven days later in the third test, which led to an investigation by the National Highway Traffic Safety Administration (NHTSA). In addition, nearly 6,000 Volts, which have been on the market for only a year, were recalled due to a mass loss of battery capacity below 80%. LG Chem, as the global leader in ternary lithium battery, produces ternary lithium battery with such safety and capacity retention rate, which indicates that ternary lithium battery is not suitable for assembly in new energy vehicles.
5. Lithium-ion iron phosphate batteries will be most suitable for the future development of electric vehicles.
It is foreseeable that in the future, the development of pure electric passenger cars and special vehicles will have the following characteristics: one is the formation of three types of models, that is, less than 1.3 tons, 1.3 ~ 1.7 tons and more than 1.7 tons. For each kilowatt-hour of electricity, the range is 10KM, 8KM and 6KM respectively, and the weight of the corresponding assembly battery is about 300KG, 500KG and 800KG respectively. Second, all the batteries are equipped with DC fast charge and AC slow charge two types of charging methods. Third, no matter the body or chassis will use new materials, take the route of lightweight composite materials, such as aluminum alloy, carbon fiber composite materials.
Therefore, for the future development of electric vehicles in China, it is no longer an important issue to ask for higher or lower energy density of power lithium batteries, because the whole vehicle should maintain a certain weight from the safety and stability design of the center of gravity. A lighter body and chassis, heavier batteries, will be a new vehicle system design - body and chassis lightweight design, iron phosphate lithium-ion battery pack for supporting design, to ensure the body weight and body center of gravity stability.
