'I don't know how long this car's battery can last?'
On the morning of June 15th, looking at another new energy vehicle driving through the window, the director of the Institute of New Energy Materials Chemistry at Nankai University, a doctoral supervisor Zhou Zhen habitually said to himself.
After more than 20 years of research in new energy materials, while looking at the growing number of new energy vehicles, Zhou Zhenxin is still worried. “The basic materials for lithium battery research, we still have a gap with world-class standards, especially high-end battery separator materials. Depends on imports'.
According to Zhou Zhen and other experts in the industry, as the 'heart' of new energy vehicles, domestically produced lithium-ion batteries (hereinafter referred to as lithium batteries) have not yet stabilized enough.
"Shikoku game" across the Pacific Ocean
Of the top 10 global power battery sales companies last year, Chinese companies accounted for 7 seats, surpassing Japan in market share, and occupying the top position in the world. It is estimated that by 2020, China’s share in the global battery market will reach seven. As a result, at present, there are more than 200 battery production companies in China, and it is the country with the largest number of lithium battery manufacturers in the world. However, this series of figures does not make people in the industry feel proud. Many people pointed out in an interview that although China has formed a relatively complete power battery industry chain. The battery industry is large enough, but it is still far from strong.
In the field of lithium batteries, there is a 'Shikoku game' across the Pacific. 'From the industry point of view, the United States has a strong R & D capabilities, is still leading the original innovation of lithium batteries, core material research and development; Japan as a battery material manufacturing country, Strict production standards, can be the first to create a new finished battery; China and South Korea as a second echelon, follow-up ... ...' Zhou Zhen explained, 'Compared to Japan, South Korea, China's low-end lithium battery products have an advantage , mainly due to the relatively cheap labor and raw materials, but in some high-end products, especially the core materials related to battery safety and manufacturing processes, there is still a large gap.
It is understood that among the four core battery materials, positive and negative electrode materials and electrolytes have been domestically produced. The only diaphragm is still the short board. The domestic diaphragm mainly supplies the low-end 3C battery market, and the high-end diaphragm is still heavily dependent on imports. The lack of core patents, diaphragms and other key materials are not for the power, not only has become a domestic lithium battery unbearable pain, but also dragged the domestic lithium battery companies 'going out' hind legs.
A person in charge of Tianjin Lishen Batteries said in an interview with a reporter from Science and Technology Daily that the most advanced ternary materials for lithium batteries, the core patents are in the hands of 3M and Argonne National Laboratories in the United States, and 3M holds regular stoichiometric ratios. The NMC material patent, Argonne National Laboratory has a layered lithium-rich material patent. At present, Panasonic, Samsung, LG and other mainstream manufacturers have to spend money to purchase the relevant patents. 'Many domestic lithium battery companies, the future to enter the international market, In the face of international giants' competition, the lack of core patents and materials technology is the biggest concern and shortcoming for Chinese battery companies in the future. 'The person in charge said.
One layer of film two days
During the interview, a battery material expert told reporters that the diaphragm is one of the key components of a lithium battery. The main material of the diaphragm is a porous polymer film, including polyethylene and polypropylene. The separator for lithium batteries has safety, permeability, Porosity and thickness have stringent requirements.
'In the lithium battery, charged ions, flow shuttle between the positive and negative electrodes, in order to form the current, and the diaphragm is located in the battery between the positive and negative electrodes, it is necessary to prevent positive and negative electrode direct contact, but also to ensure the smooth electrolyte ion “Chow Zhou explained vividly that the battery electrolyte is like a river, Lithium ion is like a boat on the river, and the diaphragm is a dam built on the bank. One diaphragm hole is like a gate on a dam. Under normal circumstances, The ions freely shuttle to the positive and negative poles to complete the charge-discharge cycle.
'The high-end separator is usually accompanied by ceramic material. If the electrolyte temperature is too high, the material will swell, the pores will close like the gate, cut off the ion exchange, so as to prevent the battery from exploding due to high temperature.' Zhou Zhen said, the diaphragm is One of the highest technical barriers for lithium-ion materials is its technical difficulties in hole-making engineering technology, substrate materials, and manufacturing equipment. 'High technical requirements, the price is naturally expensive, almost accounted for more than 10% of the total cost of the battery.'
At present, the world's best lithium battery separator materials are from two Japanese companies, Asahi Kasei Corporation and Tosei Chemicals. Ninety percent of the domestic lithium battery aluminum plastic film market is also monopolized by Japanese manufacturers such as Showa Denko. Engineer of Tianjin Lishen Company told the reporter. , Compared with Japan, China's high-end diaphragm gap is obvious. The domestic diaphragm product consistency is not high, there are problems such as porosity not up to standard, thickness, pore distribution and uneven pore size distribution.
Diaphragm quality directly affects the battery capacity, charge and discharge cycle life, fire-retardant anti-explosive safety performance and other indicators. Industry insiders with emotion: 'one layer of diaphragm two heavy days, moving past is a sunny day!'
Domestic diaphragm needs urgent breakthrough
Lithium battery separator manufacturing process is mainly divided into wet process and dry process. During the interview, the reporter learned that China has entered the world's first square array in the dry process, but in the field of wet diaphragms, although domestic enterprises have mastered methods, The overall situation is still difficult to compete with foreign giants. In addition, the core production equipment is also mainly dependent on imports.
According to the data, in 2017, the domestic lithium battery market reached a total of 113 billion yuan, of which the lithium battery power is about 60 billion yuan. The "Energy-saving and new energy automobile industry development plan (2011-2020)" issued by the Ministry of Industry and Information Technology also shows , By 2020, the production capacity of pure electric vehicles and plug-in hybrid vehicles in China will reach 2 million units per year. According to the estimates of the Battery Industry Association, the demand for high-quality automotive battery separators in China each year will reach several. Billion square meters.
'If lithium battery development is not controlled by people, diaphragms and other high-end materials can't be avoided!' Wu Mengtao, general manager of Tianjin Bamo Co., Ltd. believes that such a huge market demand, completely dependent on foreign manufacturers, is not only unrealistic, but also will be domestic power lithium batteries. The greatest hidden trouble.
High-end diaphragm technology has a very high threshold, not only to invest a huge amount of money, but also to have a strong R & D and production team, skilled technology and a high level of production lines. 'For wet manufacturing processes, resin materials and additives Extrusion mixing process and stretching process are the two core difficulties. 'Zhou Zhen believes that if domestic diaphragm companies want to do more, they must deal with the basic material surface treatment process, adhesive formulation process, product stamping and stretching and other related materials. , Equipment and process control in the three major areas of 'make up', in addition, in the upper reaches of the diaphragm industry chain, including domestic coating machines, including core production equipment also need to catch up, as soon as possible to achieve a greater breakthrough in domestic production.
Like mountaineering, the closer to the top of the hill is the hope of a successful summit, the more effort it will take! “ Zhou Zhen said.
