Lithium iron phosphate energy density is difficult to increase

Recently, the former CCTV host Chaijing filmed the smog documentary "Under the Dome" and instantly exploded the circle of friends and Weibo. When it comes to the causes of smog, motor vehicle pollution cannot escape responsibility. Therefore, in the automobile manufacturing industry, the development of new energy vehicles has always been recognized as one of the effective ways to achieve energy conservation and emission reduction.

On February 16, the Ministry of Science and Technology issued the "National Key Research and Development Plan New Energy Vehicle Special Implementation Plan (Consultation Draft)", which proposed specific targets for batteries and motors to solve the problem of new energy vehicles: 2020. We will establish a sound science and technology system and industrial chain for the power system of electric vehicles, and provide technical support for the realization of 5 million new energy vehicles by 2020.

As we all know, the three core technologies that affect the development of new energy vehicles today are batteries, motors, and electric controls. At present, among the three, the technology of electrical and electronic control is relatively mature. Therefore, batteries as the heart of electric vehicles are facing the biggest technical challenges.

Lithium-iron phosphate technology route challenges

At present, China's automotive power battery technology route is the same as the United States to choose the same route of lithium iron phosphate. There is no doubt that lithium-iron phosphate batteries have many advantages: they are stable and relatively cheap, but their energy density (more energy density can better solve the mileage problem) has very limited room for improvement. It is understood that the energy density of the lithium iron phosphate battery monomer battery can reach 157Wh/kg, but the energy density of the monomer battery is reduced to 100Wh/kg.

According to the goals mentioned in the "Energy Conservation and New Energy Vehicle Industry Development Plan (2012-2020)" promulgated by the State Council, the energy density of the power cell module will reach 150 Wh/kg by 2015(converted into a single battery, Its energy density needs to reach about 170-190Wh / kg). According to a professional engaged in the development of power cell technology, in fact, the energy density of lithium iron phosphate can only reach 130Wh / kg. Therefore, from this point of view, lithium iron phosphate cannot fully meet this requirement.

In contrast, ternary materials, which are now widely considered by the industry to be the mainstream market in the future, perform better. The energy density ratio of ternary lithium batteries can reach 170Wh / kg, which means that batteries of the same weight and ternary materials can reach the same range. 170 kilometers, lithium iron phosphate can only reach 130 kilometers. In addition, the low temperature and consistency of the ternary is better than that of lithium iron phosphate. The only deficiency is that only the safety is slightly inferior to that of lithium iron phosphate.

Three element material lithium battery sets numerous advantages in one, then why three element material has not been commercialized? The professional told the author, in fact, the current international mainstream car use of ternary material has been very common, but relatively few domestic use, the main reason is the lack of domestic research and development started late and early attention. "Although the future of ternary materials must be a trend, if the price of ternary materials continues to rise, lithium iron phosphate will still have the greatest advantage. In short, ternary, lithium iron phosphate, lithium manganese, and some hybrid materials will still coexist in the market for a long period of time.

Cost and Technology Breakthrough as a Constraint of Domestic Industrial Development

At present, power batteries account for nearly 50 % of the total vehicle cost of pure electric vehicles. Therefore, the price has undoubtedly become a major constraint on the development of the battery industry. "But battery costs will show a gradual downward trend. Optimistically, the cost will be halved after five years. "An industry insider told the author," This also depends on the degree of industrialization to help, once the industrial chain mature, the cost of mass production can be reduced. "

It is reported that at this stage, more than 60% of the power battery supply in the market comes from foreign capital or joint ventures. According to this industry analyst, it is true that in the early stage of industrialization, car manufacturers will tend to choose imported or joint venture brand batteries. To reduce their risk, "However, due to cost and access issues, they will increasingly consider the use of domestic batteries." In the future, domestically developed battery companies such as ATL, Lishen, Guoxuan, Wanxiang Products with companies such as AVIC Lithium will usher in a period of rapid growth.

Of course, in addition to the cost factors, technological breakthroughs are also indispensable. Although the R&D status quo of China's battery companies is independent R&D, "but there are not many good ones, it is difficult to enter the world's top team. According to reporters, the difficulty in battery development lies in energy density. For example, the average energy density of Japanese batteries is 30-40 % of the Chinese average, and the number of charges can reach several times that of China. However, believe that with the new energy car industry chain continues to heat up, domestic battery research and development will have a huge breakthrough.

The page contains the contents of the machine translation.