At the centralized charging station in Shenzhen, more and more electric vehicle drivers are using charging stacks compatible with multiple powers to charge their vehicles.

　　At the centralized charging station in Shenzhen, more and more electric vehicle drivers are using charging stacks compatible with multiple powers to charge their cars. In addition, with the continuous breakthroughs in power battery technology, the energy density and power density of lithium batteries have increased concurrently. This has increased the driving range of electric vehicles, and on the other hand, it has also made the replenishment time comparable to that of fuel vehicles. "Quick charge" is possible. In the accelerated iteration of technological innovation, electric vehicle users are gradually bidding farewell to the long-troubled "charging anxiety".

　　"Power Sharing" Charging Reactor Scheme

　　The matrix flexible charging stack technology can not only meet the current battery charging needs, but also meet the future "battery upgrade" needs, avoiding repeated dismantling of charging piles

　　As of the end of last year, my country had 450,000 charging piles of various types, which was 14 times that of the end of 2014. The ratio of vehicles to piles nationwide was about 3.8:1. However, while the construction of the charging network is progressing steadily, there is also a certain degree of structural supply shortage. The misallocation of resources has led to the coexistence of "difficult charging" and the phenomenon of a large number of idle public charging piles. In addition, for a long time, most of the public charging piles for electric vehicles put on the market are fixed-power charging piles, and the design of charging piles has been considered to meet the current automotive battery standards. 40kW, 60kW, 80kW, 110kW... With the increasing power of newly launched models, charging piles will face replacement or expansion.

　　The coexistence of electric vehicles with multiple powers is already a fait accompli in the electric vehicle stock market. Therefore, in centralized charging stations, how to improve the power compatibility of charging equipment is the key. "In the case of the same charging current, when the voltage is increased to 1000V, if you still charge a car with a voltage platform of 350V, the power utilization rate of the existing technical solution is only less than one-third of the original, and the equipment utilization rate is particularly low. "Shenzhen Aotxun Power Equipment Co., Ltd. Chairman Xiao Xia said, "The charging stack technology can not only meet the current battery charging demand, but also meet the future "battery upgrade" charging demand, avoiding the repeated dismantling of charging piles. ".

　　It is reported that the matrix flexible charging stack technology developed by Auto Motion integrates all or part of the charging modules of electric vehicle charging stations, and dynamically allocates the charging modules according to the actual charging power required by the electric vehicle through the power distribution unit. That is to say, in the charging station using charging pile technology, after the same charging pile power sharing, it can not only meet the 100kW battery charging, but also meet the 300kW battery charging, ensuring that each new energy vehicle can be charged with the maximum power. In Shenzhen, there are currently more than 80 centralized charging stations for flexible charging stacks invested, constructed, and operated by Auto Motion.

　　"For operating vehicles such as taxis and trucks, the power adaptability of the centralized charging station directly determines the convenience of charging." said Ni Feng, deputy director of the International Department of Guodian NARI Technology Co., Ltd., "At the centralized charging station In the application scenarios of the new technology, the charging reactor technology has the characteristics of accurate and efficient matching, which will undoubtedly be very useful."

　　Tap the potential and high-power fast charge

　　It is generally believed that the "fast charging" of electric vehicles refers to the charging technology in which the battery is charged from 0% to 80% in less than 30 minutes

　　At the recent seminar on high-power charging of electric vehicles, CATL showed the participants the charging process of super-iron-lithium batteries using the "super-iron-lithium + high-energy-density fast-charging graphite" system. The product can be charged with "5C". The demonstration process takes only 7 minutes and 12 seconds to complete 20% to 80% charging, and 20% to 100% charging takes only 13 minutes and 8 seconds.

　　Energy storage technology expert and Ecoflow founder Dr. Wang Lei said, “Ultra-high-power charging uses high-voltage DC technology, which, vividly speaking, is to dump electricity into the battery.” The unit "C" in "5C" refers to the charge rate, which can be understood as the charge and discharge rate. The charge-discharge rate of a lithium-ion battery determines how quickly electrical energy can be stored in the battery, or how quickly the energy in the battery can be released. The current of "1C" takes 1/1=1 hour from full charge to discharge; "2C" means 1/2 hour, which is 30 minutes; 5C means 12 minutes. It is generally believed that the "fast charging" of electric vehicles refers to a charging method with a charging current greater than 1.6C, that is, a technology that takes less than 30 minutes to charge from 0% to 80%.

　　The core technology of lithium battery fast charging is to accelerate the speed of lithium ions moving between the positive and negative electrodes through chemical system and design optimization without affecting the battery life and reliability. Dr. Shengwei Wang, head of the fast charging project of Ningde Times New Energy Co., Ltd., said that on the graphite surface of the negative electrode, the Ningde Times adopted the "fast ion ring" technology, which is equivalent to creating a high-speed track on the graphite surface, which greatly accelerates the lithium ion in the graphite surface. The embedding of the layer, the modified graphite takes into account the characteristics of super fast charging and high energy density. In addition, the heat dissipation rate inside the battery is also an important factor affecting the rate performance. If the heat dissipation rate is slow, the heat accumulated during high-rate charging and discharging cannot be transferred out, which will affect the reliability and life of the lithium-ion battery. The fast charging products developed by CATL are equipped with a self-developed thermal management system, which can fully identify the "healthy charging range" of a fixed chemical system in different environments, and broaden the operating temperature range of lithium batteries.

　　"The demand for high-power charging is very clear. There are urgent needs for commercial vehicles, taxis, online car-hailing and other vehicles at home and abroad. Especially in large cities such as Beijing, Shanghai, Guangzhou and Shenzhen where parking spaces and charging pile resources are scarce, it is difficult for car owners to In the case of finding a parking space for charging, there will be a strong demand for high-power charging.” Ni Feng said, “but high-power fast charging products above 300kW are in their infancy around the world, with battery heating, equipment volume, safety isolation, etc. Technical issues need to be optimized, and there is a long way to go from mature technology to mature market; in addition, there are also infrastructure supporting issues such as the construction of charging stations and power grids that have yet to be resolved."

　　Management and service need to be more refined

　　Experts said that in order to promote the healthy development of electric vehicles, intelligent and refined management of charging services is the general trend.

　　my country has ranked first in the global production and sales of new energy vehicles for three consecutive years. As of the end of last year, the cumulative sales of new energy vehicles in my country reached 1.8 million, more than 50% of the cumulative global sales. "According to market trends, after 2020, there will be more and more high-power electric vehicles with more than three or four hundred kilowatts." Ni Feng believes that "whether it is the charging stack or the battery itself, there are no technical problems." In addition, although early operators did not consider power expansion, in recent years, more and more operators have reserved space for expansion in centralized charging stations. It can be directly expanded-just add the corresponding modules."

　　Liu Yongdong, deputy director of the Standardization Management Center of the China Electricity Council, said that in terms of charging methods, the future trend of electric vehicles will be "private AC charging pile daily slow charging" and "public fast charging" for a long time to coexist and combine with each other. "For urban families who use electric vehicles to commute, using private charging piles to charge at home after get off work, long-term slow charging can already meet most of the needs; using fast charging at charging stations will be more of a necessary supplement." .

　　The optimization of the management system in the charging field is expected by many experts. Ni Feng cited an example of a cooling solution for the power module of a charging station. The mainstream cooling solutions for power modules include water cooling and air cooling. The former has a long service life and high reliability, but it is expensive; the latter is inexpensive, but requires high environmental requirements, and is prone to dust clogging after long-term use. "The domestic bidding mechanism of the'lowest price' has led many operators to adopt the air-cooling model, but all of them need to be replaced after less than two years of use. The overall cost of use is higher than using water-cooling," Ni Feng said. .