The energy density is 300Wh/kg, the driving distance exceeds 500 kilometers on one charge, and the ten-minute fast charging is in the early stage of the development of electric vehicles, facing various difficulties, (we have to think) what kind of battery do we need? What kind of battery do we need? Electric vehicles? On November 21, Qi Lu, a professor at Peking University and chairman of the Lithium Battery Davos Academic Committee, made a series of questions at the 6th my country Lithium Battery New Energy Industry International Summit Forum (ABEC2018, Lithium Battery Davos) .
In the past two years, my country's electric vehicle industry has developed rapidly. The sales volume of new energy vehicles has increased from more than 300,000 in 2015 to 777,000 in 2017, and 860,000 in the first October of this year. Ten thousand vehicles mark. With the rapid development of the industry, electric vehicle safety accidents occur frequently. At Lithium Davos, the annual battery industry event, battery safety issues have become the focus of attention of all parties. Qilu believes that too much pursuit of high energy density, high cruising range, fast charging, etc. will only make the safety problems of electric vehicles more and more terrible. As an electric vehicle with basic functions, the cruising range is 200-300 kilometers, which can fully meet the needs of daily travel.
Technical deviation leads to new security risks
I saw a report from the China Automotive Industry Corporation, saying that there have been at least 50 accidents this year. As long as an accident occurs, no matter which company or brand it is, the entire new energy vehicle industry will be affected, and the lithium-ion battery industry will also be affected.
According to Qilu's statistics, the number of electric vehicle accidents is far more than 50. Combustion, explosion, and various accidents, public and undisclosed, number over a hundred every year. While not all accidents are blamed on EV batteries, there are a variety of causes. However, the safety and reliability of batteries have become an important factor restricting the development of the electric vehicle industry. Qilu thinks.Also read:12V 400AH Lithium ion Battery
In the eyes of industry insiders, the reason why the lithium battery industry is going further and further on the road of high energy density and high cruising range is that the company pays too much attention to government subsidies, which are related to the fact that the subsidies are led by vehicle companies. If there is no government subsidy, the electric vehicle industry and the lithium battery industry will not develop at the current speed if they only rely on market spontaneity. This is also the consensus of people in the battery industry. However, with the gradual decline of government subsidies, the double-edged sword use of government subsidies has gradually become prominent.
What is the real purpose of our haste to increase energy density? Is it for environmental protection or excessive environmental protection? Is it for saving or excessive saving? Do we want mileage for mileage or excessive? Unscientific cost requirements have also added potential safety hazards. In recent years, popular practices in the battery industry such as simplified system design and increased capacity and volume of single cells have added potential safety hazards to batteries. Cheng Jun, dean of the research institute of Lixin (Jiangsu) Energy Technology Co., Ltd., said.
Now all of your actions, from operations to production, to the design of electric vehicles, to the energy density of batteries and the direction of technological development, are all linked to subsidies. It is necessary to keep up with the development of the policy, but the indicators stipulated by the policy have been raised too fast, which also makes the company tired of coping and it is difficult to seriously develop products. Liang Rui said in his speech that in terms of cruising range, it will be 250 kilometers in 2016, 300 kilometers in 2017, and more than 400 kilometers in 2018, and 500 kilometers or even 600 kilometers next year; in terms of energy density, it will be 140Wh in 2018 /kg, in 2019, there are many legends in the market. Some people say that it will be raised to 180Wh/kg. Regardless of whether the policy is like this, the vehicle companies have already started to take action. Now with many car companies are required to be more than 160Wh.
Pushed away by policies and vehicle companies in the past two years, battery companies were busy upgrading technology and financing and expanding production, and did not pay enough attention to safety issues. Now, with the decline of policy subsidies, the market has begun to play a role, and the industry's low tide is coming. , The power lithium battery industry began to pay more attention to safety issues.
At the 2018 Lithium Battery Davos, people in the battery industry proposed solutions to improve battery safety from various perspectives. Wang Qingsheng, a distinguished professor at Peter the Great University of Technology in St. Petersburg, Russia, proposed the development direction of quasi-solid lithium technology. Quasi-solid state is to combine the advantages of solid electrolyte and liquid electrolyte application. Representatives of Han’s Laser (002008.SZ) proposed solutions from the battery processing technology; Lithium-ion battery film suppliers such as Lanketu proposed solutions from the innovation of battery separator materials; representatives of battery electrolyte companies proposed new flame-retardant materials, etc. Read related testimonials:Lithium Battery Manufacturers
Even the charging operation company has proposed its own solution. Yu Dexiang, chairman of Qingdao Telecom, said in his speech that the cloud charging system of Telecom without pile charging and group management and group control can monitor the status of electric vehicles during the charging process. Monitoring to detect battery problems in time and improve the safety of electric vehicles. The possibility of burning the car will be reduced by 70% if it is charged through the network of special calls.
Many people in the industry said that there is no one-size-fits-all method. The safety of electric vehicles is not only a problem for battery companies, but a system engineering that requires the joint efforts of material suppliers, battery equipment suppliers, battery companies and OEMs. .
Diversification of technical routes
What kind of lithium-ion battery technology does the electric vehicle industry need? Is it necessary to solve the problem through high energy density? Qilu suggested that battery companies relax their thinking and consider this issue according to the actual situation. Today there are still a large number of lead-acid batteries entering off-road areas on a scale of hundreds of thousands and millions of vehicles. Then there's the Ni-MH battery, an almost-forgotten battery technology that's been used in Japanese hybrids for a long time. my country's battery and electric vehicle companies should also rethink the direction of technology from the perspective of market and practicality, especially from the perspective of safety.
But with regard to high-nickel ternary batteries, solid-state batteries, hydrogen fuel cells and other new technologies that are becoming more and more popular in the industry, Qilu also recommends the company to remain cautious and calm. For example, high-nickel ternary batteries are more likely to release a large amount of heat than lithium manganate and lithium iron phosphate materials, and the safety challenges are even greater.
In Qilu's view, some solid-state battery technologies that have been launched on the market are not strictly speaking solid-state battery technologies. There are still key technical difficulties in solid-state battery technology to be overcome: can the energy density be improved only by converting the electrolyte into a solid-state electrolyte? Can the safety of the battery be improved? Moreover, if there is no revolutionary change in the pole piece technology, The conductivity problem cannot be solved with today's manufacturing methods of lithium-ion battery pole pieces.
Even the hydrogen fuel cell technology, which is regarded as the ultimate solution to new energy vehicles, Qilu and his students have done calculations. If 300 million electric vehicles in my country become hydrogen fuel cells, the consumption of fresh water in order to extract hydrogen The amount is very huge, and it is simply not something that a water-short country like my country can bear. Moreover, the process of extracting hydrogen energy also consumes electricity.
In specific areas, hydrogen fuel cells can be combined with lithium-ion batteries to solve problems in terms of safety and cruising range. Instead, it's too early to see. Qilu thinks.
Faced with the advent of the post-subsidy era, some companies have expressed their consideration of other technical routes other than ternary lithium batteries. In the past two years, many people in many industries have asked, what will happen to lithium iron phosphate? The representative company here clearly stated that as an OEM, power lithium batteries must choose a diversified technical route in the future. Ternary lithium battery is the main direction, but lithium iron phosphate will definitely be our choice in the future. Lithium iron phosphate has its particularity, especially suitable for small vehicles. Ni Shaoyong, deputy general manager of Chery New Energy Vehicle Technology Co., Ltd. and director of the research institute, said in his speech that in the next one to two years, the market demand for lithium iron phosphate batteries will increase.
Ma Zhonglong, deputy general manager of Honeycomb Energy Technology Co., Ltd. invested by Great Wall Motors, proposed the research and development direction of cobalt-free positive electrodes, saying that the company has mass-produced cobalt-free positive electrode cells, which significantly reduce the cost compared with traditional ternary materials.