The development of the electric vehicle industry requires tapping high-power fast charging

With the continuous breakthrough of power battery technology, the energy density and power density of lithium batteries have been improved in parallel. This aspect has improved the driving range of electric vehicles. On the other hand, it has also made the “fast charge” comparable to that of fuel vehicles. may. In the accelerated iteration of technological innovation, electric vehicle users are gradually bidding farewell to the long-standing "charging anxiety."

"Power Sharing" charging reactor solution

Matrix flexible charging reactor technology can not only meet the current battery charging requirements, but also meet the future "battery upgrade" requirements, avoiding the repeated withdrawal of charging piles.

As of the end of last year, China had 450,000 types of charging piles, 14 times that of the end of 2014, and the national vehicle-pile ratio was about 3.8:1. However, while the construction of the charging network is steadily advancing, there is also a certain degree of structural supply shortage. The mismatch of resources has led to the coexistence of “difficulty in charging” and the large number of idle charging of 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 is considered to meet the current standard of automobile batteries. 40 kW, 60 kW, 80 kW, 110 kW... As the new models are getting more and more powerful, the charging piles will face replacement or expansion.

The coexistence of multiple power electric vehicles is already a fait accompli of the electric vehicle inventory market. Therefore, in a centralized charging station, how to improve the power compatibility of the charging device is the key. "With the same charging current, when the voltage is raised to 1000 volts, if the 350 volt car is still charged, the power utilization rate of the prior art solution is less than one third, the equipment utilization rate. "Specially low." Xiao Xia, chairman of Shenzhen Aotexun Power Equipment Co., Ltd. said, "The charging reactor technology can meet the charging requirements of the current battery, and can also meet the charging demand of the future 'battery upgrade', avoiding the repetition of the charging pile. Withdraw construction."

It is reported that the matrix flexible charging reactor technology developed by Autoxun integrates all or part of the charging modules of the electric vehicle charging station, and dynamically allocates the charging module according to the actual charging power of the electric vehicle through the power distribution unit. That is to say, in the charging station using the charging reactor technology, after the same charging pile power is shared, it can satisfy the charging of 100 kW battery or the charging of 300 kW battery, ensuring the maximum power of each new energy vehicle. Charging. In Shenzhen, Autotech has invested, built and operated flexible charging reactors with more than 80 centralized charging stations.

Since December last year, the Shenzhen Standardization Technical Document “Electric Vehicle Flexible Charge Reactor Technical Requirements”, which was jointly organized by Shenzhen Municipal Market Supervision Administration and Shenzhen Development and Reform Commission, was implemented in Shenzhen. This is the first in China. The local standard for flexible charging reactors for electric vehicles. As the leading enterprise in the subdivision industry of electric power automation, Shenzhen Autotron Power Equipment Co., Ltd. is the lead drafting unit of this standard.

"For taxis, trucks and other operating vehicles, the power adaptability of centralized charging stations directly determines the convenience of charging." Ni Feng, deputy director of the international department of Guodian NARI Technology Co., Ltd. said, "At the centralized charging station. In the application scenario, the charging reactor technology has the characteristics of precise and efficient matching, which will undoubtedly be of great use."

Tap potential high power fast charge

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

At the pilot seminar on high-power charging of electric vehicles held recently, the Ningde era showed the participants the charging process of the super-iron lithium battery using the "super iron lithium + high energy density fast charge graphite" system. The product can be charged "5C", the demonstration process only takes 20% to 80% of the charge in 7 minutes and 12 seconds, and 20% to 100% of the charge, it only takes 13 minutes and 8 seconds.

Dr. Wang Lei, an expert in energy storage technology and founder of Ecoflow, said, "Ultra-high-voltage DC technology is used for ultra-high power charging. In an image, it is dumping electricity into the battery." The unit "C" in "5C" refers to the charging rate, which can be understood as the charging and discharging rate. The charge-discharge rate of a lithium-ion battery determines how quickly the energy can be stored in the battery, or how quickly the energy in the battery is released. The current of "1C" is completely 1/1 = 1 hour from full charge to discharge; "2C" is 1/2 hour, that is, 30 minutes; 5C is 12 minutes. It is generally believed that the "fast charge" of an electric vehicle refers to a charging method in which the charging current is greater than 1.6 C, that is, a technique of charging from 0% to 80% for less than 30 minutes.

"The demand for high-power charging is very clear. There is an urgent need for vehicles such as commercial vehicles, taxis, and network-related vehicles at home and abroad. Especially in large cities such as Beishangguangshen, where parking spaces and charging pile resources are scarce, it is difficult for owners. When the parking space is charged, there will be a strong demand for high-power charging.” Ni Feng said, “But the high-power fast charging products above 300 kW are in the initial stage in the world, battery heating, equipment volume, safety isolation. Other technical issues have yet to be optimized, and there is a long way to go from mature technology to mature market. In addition, infrastructure support issues such as charging station construction and power grid supply have yet to be resolved."

Management and services 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 trend of the times.

China has been ranked as the world's largest producer of new energy vehicles for three consecutive years. As of the end of last year, the cumulative sales of new energy vehicles in China reached 1.8 million units, accounting for more than 50% of the global cumulative sales. "According to market trends, after 2020, there will be more and more high-power electric vehicles of more than three hundred and four hundred kilowatts." Ni Feng believes that "no matter whether it is a charging reactor or a battery itself, there is no problem in technology." Although early operators did not consider power expansion, in recent years, more and more operators have reserved space for expansion in centralized charging stations. "After the emergence of more power charging requirements, stations, piles, and stacks can directly Expansion - you can add the corresponding module."

Liu Yongdong, deputy director of the China Electricity Council's Standardization Management Center, said that in the way of charging, the trend of electric vehicles in the future will be the long-term coexistence and mutual integration of "private charging and charging piles daily slow charging" and "public fast charging and charging". “For urban families who use electric vehicles for commuting, they use private charging piles to charge at home after work. Long-term slow charging can meet most of the needs; using fast charging at charging stations will be a necessary supplement.” .

The optimization of the charging field management system is expected by many experts. Ni Feng cited an example of a cooling scheme for a charging station power module. The mainstream cooling module of the power module has water-cooling and air-cooling modes. The former has a long service life and high reliability, but the price is expensive. The latter is inexpensive, but has high environmental requirements, and is prone to dust clogging due to long-term use. The "domestic bidding" is a mechanism that allows many operators to adopt the air-cooling mode, but it needs to be replaced in less than two years. The comprehensive cost of use is higher than the use of water cooling." Ni Feng said .

"We talk about charging technology and management and service improvement today, all of which are based on the healthy development of electric vehicles." Ni Feng said, "The most fundamental driving force of electric vehicles still comes from electric vehicles themselves, from the ecological adjustment of the entire industry chain. And change. What we are most concerned about is that after the relevant subsidies are canceled, the desire of users to spontaneously consume and use electric vehicles is strong, which is the key to the long-term development of the entire industry."

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