Per reporter: Li Shuo Per editor: Pei Jianru
With the acceleration of sales of new energy vehicles, the competition for vehicle mileage has become more and more intense.
A few days ago, the first NEDC pure electric endurance of more than 1,000 kilometers of GAC AION LX Plus was officially launched, making 1,000 kilometers of endurance once again a hot topic in the car circle. In fact, a number of car companies are promoting the progress of pure electric models with a range of 1,000 kilometers, for example, the Mercedes-Benz brand recently released the EQ family concept car VISION EQXX with a range of more than 1,000 kilometers; the 1,000-kilometer endurance pure electric models of new car-making forces such as Weilai and Zhiji will also be listed one after another.
Image source: Courtesy of the enterprise
"From a technical point of view, 1,000 km endurance is completely achievable, but with high endurance comes the problems of higher safety technology requirements and difficult cost control." It is almost impossible to take into account fast charging, safety and cost while maintaining a range of thousands of kilometers. Ouyang Minggao, academician of the Chinese Academy of Sciences and vice chairman of the China Electric Vehicle 100 Association, believes that the thousand-kilometer endurance is more likely to appear in luxury SUV models, on the one hand, there is room for installing batteries, on the other hand, customers are also willing to pay for the price range of products driven by the market.
Technically feasible Necessity is controversial
Although the final mileage is similar, the technical means used by various car companies are different.
Yu Qingjiao, secretary general of the Zhongguancun New Battery Technology Innovation Alliance and chairman of the Battery Hundred Association, said that in order to achieve a cruising range of 1,000 kilometers, GAC AION LX Plus is equipped with NCM ternary lithium battery pack, NIO ET7 is equipped with semi-solid-state batteries, Zhiji L7 is equipped with silicon-doped lithium batteries, BYD Ocean-X continues blade batteries, Tesla is equipped with electrodeless ear batteries, and the new pure electric platform changes the original structural design. "It can be seen that in order to achieve a 1,000-kilometer endurance, some car companies change the physical structure of the battery, and some car companies change the chemical structure of the battery, but whether it is a physical structure or a chemical structure change, it is necessary to consider safety, cost, vehicle quality, etc." Yu Puritan said.
It is understood that the battery life of new energy vehicles is jointly determined by multi-dimensional factors, including battery capacity, thermal management, lightweight, wind resistance, motor efficiency, etc., of which improving battery capacity is the most effective way to improve the mileage. However, some people believe that relying only on the number of stacked batteries to improve endurance will lead to a sharp increase in battery costs, difficulty in arranging space in the car, easy to get out of control of thermal management, and low efficiency of the whole vehicle.
"If I don't have my own charging pile, I won't consider the long battery life." Shen Hongwei (pseudonym), a Beijing car owner who has purchased a pure electric car, told the "Daily Economic News" reporter that whether the driving range is 300 kilometers or 1,000 kilometers, it is inevitable to face the demand for replenishment.
"No matter how long the battery life is, it must be charged, if it is not a self-appliance pile, the time to queue up and wait for charging is also indispensable, but the frequency of charging is reduced." Therefore, I think that only by shortening the charging time and perfecting the charging layout can the battery life anxiety be completely solved. Shen Hongwei said.
In fact, not only on the consumer side, there are doubts, but the necessity of 1,000 km endurance is also controversial in the industry. Volkswagen Group China CEO Feng Sihan has said that Volkswagen has no plans to launch a 1,000-kilometer endurance electric vehicle. "Achieving a cruising range of 1,000 kilometers is indeed a matter of great concern in marketing, but whether it needs to be used as an industry goal is debatable." He believes that in the absence of a substantial breakthrough in battery technology, high-endurance electric vehicles need to be equipped with heavier batteries, so they must be paired with extremely high-cost, lighter bodies, so that the cost of the whole vehicle will become higher and higher.
Xu Xiangyang, a professor at Beijing University of Aeronautics and Astronautics, also told reporters that mileage anxiety has always been the pain point of electric vehicles, and the introduction of long-range models is an important measure for automobile companies to solve the problem of consumer mileage anxiety, and the progress of battery-related technologies has laid the foundation for the increase in the mileage of pure electric vehicles. Therefore, long-term long mileage is definitely a development direction, but not all electric vehicles need a long mileage of 1000 kilometers, consumers still have to choose their own models according to the use of the use.
Winter battery life attenuation problem to be solved
In fact, the problem of endurance anxiety that the 1,000-kilometer endurance model focuses on solving is more prominent in winter.
According to the "China Small New Energy Vehicle Low Temperature Endurance White Paper" released by the China Academy of Automotive Engineering, the low temperature attenuation data based on 53 new energy vehicles shows that more than half (65.4%) of the vehicles have a low temperature mileage retention rate between 52.8% and 67.2%, and the median value of their normal distribution is 59.95%.
At the same time, during the period from 2012 to 2020, the average value and distribution range of the low-temperature mileage retention rate of 53 new energy vehicles have not changed significantly, which means that there is still no significant solution to the problem of winter endurance attenuation of power batteries.
"At minus 15 degrees to minus 20 degrees, the power battery mileage is almost waist-cut, and such a mileage retention rate has a very large impact on small new energy vehicles with a short driving range." Ouyang Minggao said that this is also a big problem in the development process of new energy vehicles in China.
It is understood that when the temperature drops, the electrolyte in the battery will become more viscous, including the rate of lithium ion migration, and the conductivity of the material itself will further deteriorate, making the battery activity decrease, thereby affecting the battery performance and capacity volatilization, which is externally manifested as the attenuation of the usable capacity of the power battery.
In response to this problem, car companies are also applying different technologies to improve. For example, some models of brands such as Weilai, Roewe, tesla and other brands use liquid cooling and constant temperature systems; some models equipped with blade batteries of BYD use "battery internal heating"; and the Volkswagen ID family uses carbon dioxide heat pump air conditioning. In addition, there are auxiliary means of software such as diesel heating systems, "timed charging" and "in-transit preheating".
Wang Zidong, deputy secretary-general of the China Automotive Power Battery Industry Innovation Alliance, told reporters that there are currently four main technical routes to solve the problem of low-temperature endurance retention of power batteries: one is to improve the low-temperature performance of the battery material system in use, especially the battery activity in the low-temperature state; the second is to find better low-temperature-resistant materials; the third is to increase the thermal insulation efficiency of the battery by physical methods; and the fourth is to replace the battery. Among them, the fastest way to solve the "cold intolerance" of power batteries is physical heat preservation and power exchange.
Daily economic news