At the beginning of this year, the website of the Ministry of Industry and Information Technology released a message that the national standard for electric vehicle conduction charging connection devices was officially revised. According to reports, the revision of the standard will further improve the charging current voltage on the basis of the current DC charging interface technical scheme in the mainland, optimize and improve the control guide circuit and communication protocol, expand the functions of agile control, plug and charge, appointment charging, etc., to meet the development of high-power charging technology and market demand, effectively ensure the universal compatibility of new and old charging interfaces, and create a good environment for the high-quality development of the new energy automobile industry.
Some market analysts pointed out that in addition to meeting the needs of electric vehicle consumers for fast charging, the revision of the standard will also create an "outlet" for the application of new technologies such as high-power charging, and open a new chapter in the development of the new energy vehicle energy replenishment business.
Tong Zongqi, director of the Information Department of the China Electric Vehicle Charging Infrastructure Promotion Alliance (hereinafter referred to as the "Charging Alliance"), said in an interview with the China Automobile News reporter that car owners will comprehensively consider factors such as charging time and parking charges when choosing charging piles, and in general, high-power charging facilities are more in line with user preferences.
It is understood that in the past, the voltage of charging piles built in China was not too high, and in order to achieve high power, a large current method was generally used. Liu Yongdong, deputy secretary-general of the China Electricity Council and secretary general of the Standardization Technical Committee of Electric Vehicle Charging Facilities in the energy industry, told reporters that increasing the current can achieve high-power charging, but the larger the current, the more the cable heats, the more serious the safety hazards. He believes that increasing the voltage is the overall solution for the next generation of conductive charging technology.
High-power charging is favored by users
Statistics from the Ministry of Public Security show that by the end of 2021, the number of new energy vehicles in the mainland will exceed 7.84 million, with a penetration rate of 13.4%, of which more than 6.4 million are pure electric vehicles. The market penetration rate of new energy vehicles in the mainland has exceeded 5% and 10% of the two important nodes, from the introduction period to the growth period, and the user's consumption behavior has gradually become clear.
With the continuous growth of new energy vehicles, the scale of charging facilities has risen. According to the Statistics of the Charging Alliance, as of December 2021, there are 2.617 million charging infrastructure units in the mainland, of which 1.147 million are public charging piles and 1.47 million are private charging piles. 2021 was the year with the largest increase in the number of charging facilities, with 597,000 public charging piles and 340,000 private charging piles.
As a result, the consumption behavior of new energy vehicle users has also begun to show a certain regularity. The Charging Alliance conducted a survey of consumers' charging behavior. Tong Zongqi told reporters that there are relatively few users who can install private charging piles in China, and their consumption behavior is relatively fixed, while the consumption behavior of public charging piles can better reflect the preferences of the market. According to reports, up to 87.9% of users choose high-power charging facilities of 120kW and above when charging, while the user selection rate of charging facilities below 60kW is only 1.6%. Among them, the number of users who choose 120~150kW high-power charging facilities is the largest, accounting for 35.1%.
In addition, the survey data also shows that online ride-hailing, taxis, and commercial vehicles are highly sensitive to charging time because of their operational and operational attributes, and almost all of them use fast-charging piles to charge during non-working hours. Tong Zongqi said: "From the survey results, the use rate of fast charging of different types of users is 90%, and they are inclined to choose high-power charging facilities of 120kW and above, of which the use rate of fast charging of online car- and commercial vehicle users exceeds 99%. Commercial vehicles are affected by factors such as high vehicle voltage platforms and large battery capacity, and the demand for high-power charging is greater. 91.2% of commercial vehicle users choose high-power charging facilities of 120kW and above for charging, which is 3 to 6 percentage points higher than other types of users. ”
Private car users are not time sensitive and are willing to enjoy the price difference of peak and valley electricity. According to the survey data, private car users choose slow charging pile charging at specific times (night or work hours), and the use rate of slow charging piles is 2.5%. Private car users prefer to choose charging facilities with charging power less than 30kW than other types of users, indicating that in the 7kW AC slow charging scenario, private car users are more willing to choose charging.
It is also understood that in terms of the perfection of the charging network construction, 54.6% of the users are satisfied, 14.4% of the users are dissatisfied, thinking that the construction of charging infrastructure needs to be further improved; 53.7% of the users believe that the current fast and slow charging construction ratio does not match the actual needs of users, charging often appears "fast charging pile idle, slow charging pile no one uses"; 50% of users believe that the surrounding environment of some charging stations is not good 41.8% of users believe that the lack of corresponding supporting facilities around the charging station is not enough to meet the daily needs of users; there are also problems such as insufficient number of charging piles, lack of charging guidelines in the station, remote location of pile construction, poor installation layout of charging piles, etc., and the construction of charging piles and the selection of hot spots need to be strengthened.
High voltage becomes the next generation of charging technology
At present, most of the mainstream models at home and abroad use a platform with a voltage of about 400V, and the fast charging capacity of the power battery cell is basically 1C. Liu Guanwei, general manager of the strategic market of Linkage Tianyi New Energy Co., Ltd., told reporters that the power of 1C fast charging is about 50 ~ 60kW, for users, even if 1C fast charging is used, it takes about 1 hour to charge, and it is the general trend to improve charging power.
Increasing the power is nothing more than increasing the current or increasing the voltage. Liu Guanwei said: "Large current will lead to charging guns, cables and power battery core components and other high heat loss, its theoretical increase in the upper limit is not large, the current mainstream charging gun maximum current limit is 500A, the charging power that can be achieved is about 200kW, many enterprises plan the high power demand is 350/500/1000kW, so 200kW is far from meeting the charging demand." ”
Since the road to increasing the current is "not far away", how about increasing the voltage? Liu Guanwei believes: "The technical route of increasing voltage can not only easily achieve a rapid increase in charging rate, but also reduce heat loss, reduce vehicle quality, optimize the power structure, and improve safety performance." 800V high-power fast charging is the future development direction of the market. ”
Liu Yongdong told reporters that the industry has reached a consensus that 800V high-power charging is the overall solution of the next generation of conductive charging technology. "Since it is called the 'total solution', the development of 800V high-power charging includes a series of elements in it, and it is not just a consideration of increasing the voltage." He said, "800V high-power charging can also support V2X, information encryption, security authentication and communication technology upgrade routes." The ChaoJi International Joint Working Group is advancing international standards. ”
According to reports, 800V high-power charging helps to improve the mechanical safety and electrical safety of the existing charging system, and further strengthens the design of electric shock protection, fire prevention and thermal safety. What's more, 800V high-power charging can introduce new applications. Liu Yongdong said: "High-power charging can be increased to 900kW, which greatly shortens the charging time and alleviates the disadvantage of long charging time of electric vehicles." With 800V fast charging, small power slow charging can be DC. ”
800V high-power charging shows a good prospect, but the 2.617 million charging piles already in the mainland do not belong to 800V high-power charging. How are these charging piles disposed of? The reporter raised this question with Liu Yongdong. He replied: "The compatibility of 800V high-power charging is very good, does not change the existing vehicle pile products, and the adapter scheme can be used for the existing charging pile to achieve a smooth transition and upgrade." ”
Liu Yongdong also told reporters several important parameters, the maximum voltage of 800V high-power charging can be extended to 1000V, or even 1.5kV, the maximum current is divided into two kinds, 500/600A with cooling system; 150 ~ 200A can not need a cooling system, the maximum power reaches 900kW, which is more than 4 times the existing charging power.
Suitable for mid-range and above models
In fact, the automotive industry is forming a boom in the development and mass production of 800V voltage platforms. For example, companies such as Extreme Kr Automobile, Xiaopeng Automobile, and BYD have set the mass production node of related models in 2022. Because of this, some people even regard this year as the first year of the development of 800V voltage platforms.
Guangzhou Wancheng Wanchong (hereinafter referred to as "Wancheng Wanchong") New Energy Technology Co., Ltd. is a charging service provider of GAC Aeon. Liang Xiangfei, deputy general manager of Wancheng Wanchong, said: "800V high-power charging has become a trend, car companies generally welcome it, and most of the vehicle companies that rank top in the sales of electric vehicles are promoting this solution. According to reports, the charging gun based on the 2015 version of the national standard and increasing the liquid cooling system developed by GAC Aian supports a maximum current of 600A, and is compatible with the 2015 version of the national standard downwards, and the weight is lighter than the current 250A national standard charging gun. GAC Aeon's 800V high-power charging module, the maximum voltage is 1000V, the charging pile power output is not less than 480kW, and can be upgraded to 600kW. The charging module device uses silicon carbide technology to improve both power density and efficiency: at a charge rate of 6C, the SOC goes from zero to 80% and requires a charging time of 8 minutes, and the SOC goes from 30% to 80% with a charging time of only 5 minutes.
However, 800V high-power charging will increase the cost, and not all models are suitable for this solution. Liang Xiangfei said: "Mid-range and above models are more suitable for 800V high-power charging, low-end cars due to the travel scenario limitations, more sensitive to cost, smaller battery capacity and other factors, not suitable for the implementation of 800V high-power charging." ”
At present, the pile with the car is one of the important marketing means for the whole vehicle enterprise to increase the sales of electric vehicles. Compared with the previous ordinary charging pile, the cost of 800V high-power charging pile is at least doubled, or even 2 to 3 times. For low-end models, the distribution of 800V high-power charging piles with vehicles will greatly weaken their price competitiveness.
In addition, Liang Xiangfei believes that there are many corresponding supporting problems to be solved in 800V high-power charging, not just the problem of charging piles. 800V high-power charging has higher requirements for power conditions, and some places need power transformation to adapt to new developments. At the same time, fast charging has certain damage to the battery, especially lithium iron phosphate batteries will have obvious attenuation after multiple fast charging, and battery companies also need to develop a battery cell suitable for 800V high-power charging. "800V high-power charging needs to be promoted as a whole, and only charging pile companies can keep up with the pace, and it is difficult to achieve the goal." Liang Xiangfei stressed. But he firmly believes that under the impetus of market demand and support policies, 800V high-power charging will soon form a "big climate".
Expert opinion
◆ Tong Zongqi, Director of the Information Department of the China Electric Vehicle Charging Infrastructure Promotion Alliance:
The public charging field should be dominated by high-power charging
Difficult charging and long charging time have always been the pain points in the use of new energy vehicles. With the increase in the number of charging piles, the dilemma of charging difficulties has been alleviated, but users' complaints about long charging time have not stopped. In order to shorten the charging time, users generally choose high-power charging. Tong Zongqi, director of the Information Department of the China Electric Vehicle Charging Infrastructure Promotion Alliance (hereinafter referred to as the "Charging Alliance"), told the China Automotive News reporter: "Judging from the situation of new public charging piles in the past 4 years, the high-power charging piles of 120kW and above have grown rapidly, of which the average annual growth rate of 180kW and above supercharge piles has reached 92.8%. He believes that from the perspective of user use scenarios, the public charging field should be dominated by high-power charging.
Tong Zongqi analyzed in detail to reporters the charging needs of electric vehicles in different application scenarios. Buses are basically charged using special facilities and are not shared with the outside world. About 50% of private and official cars use private charging piles built in residential areas, and about 50% of vehicles often use public charging piles to replenish energy. About 50% of the logistics vehicles use public charging piles, and about 50% of the vehicles use the self-use charging piles built by the logistics center to supplement energy, and this part of the charging pile is rarely shared with the outside world. 80% of commuter shuttles are charged using public charging piles, and only 20% of vehicles have exclusive charging facilities. Sanitation vehicles, muck trucks, etc. use almost 100% exclusive charging facilities.
"The future development trend may be that electric passenger cars will be mainly charged in residential areas, supplemented by public charging, and supplemented by electricity replacement." It is expected that private charging piles will account for 65% of the new charging piles, and the amount of charging provided by private charging piles will be less than 40%; the demand for super fast charging in the public and private sectors is more urgent, and the number of fast charging piles will increase by 500,000 units. Tong Zongqi said, "Charging in the public domain is based on safety, high-power charging is the technical direction, and multiple technical routes will coexist." ”
In order to accelerate the development of high-power charging, the Charging Alliance has put forward a number of recommendations. Tong Zongqi introduced: "It is hoped to accelerate the landing of high-power charging technology standards, unify the construction orientation of public and special infrastructure in various provinces and cities, focus on high-power charging facilities, supplemented by slow charging and power replacement; government subsidies need to vigorously support the upgrading and application of high-power charging technology; strengthen the safety supervision of charging stations, increase safety facilities, and improve the level of safety protection." ”
◆ Liu Yongdong, Deputy Secretary-General of China Electricity Council and Secretary-General of the Standardization Technical Committee of Electric Vehicle Charging Facilities in the Energy Industry:
High-power charging calls for standards first
In 2015, the mainland has formulated the standard for charging piles for new energy vehicles, namely the Conducted Charging System for Electric Vehicles - Part 1: General Requirements (GB/T18487.1-2015) (hereinafter referred to as the "2015 Edition of the Standard"). After years of practice, this standard system has exposed some problems. Liu Yongdong, deputy secretary-general of the China Electricity Council and secretary general of the Technical Committee for the Standardization of Electric Vehicle Charging Facilities in the energy industry, introduced it to the reporter of China Automobile News.
In terms of safety, the 2015 version of the standard has problems such as the connection end face does not meet the requirements of IPXXB; the mechanical strength of some key structures is weak; there are safety hazards in the design of indirect locking electric lock; PE (protective ground wire) is interrupted, the human body resistance access PE cannot be detected; the guidance circuit has no hardware node to transmit the emergency shutdown signal; and the definition of many safety-related electrical indicators is missing.
In terms of reliability, the 2015 edition of the standard has problems such as high failure rate of electronic locks, low reliability of plug and socket connections, and unreasonable design of interface size tolerances.
In terms of compatibility, the 2015 version of the standard does not consider forward and backward compatibility.
Liu Yongdong said: "High-power charging will use a high-voltage platform of more than 1000V, which will increase the energy stored by Y capacitors and further amplify the safety risks brought by IPXXB that vehicle sockets cannot meet IPXXB." ”
In addition, the 2015 version of the standard high-power charging only considers increasing the current, and does not propose a solution to the safety problems that may be brought about by the increased voltage. Liu Yongdong believes that the voltage raising platform, which involves the adjustment of the voltage platform of the whole vehicle, has a large impact and the safety of the charging system (such as the electric shock energy brought by the high voltage) cannot be ignored.
Mainland China has built 2.617 million new energy vehicle charging facilities, if the development of charging technology can not be compatible with previous equipment, not only may cause a waste of resources, but also is not conducive to improving the user's charging experience. Liu Yongdong said: "Not the connector end face is similar to represent compatibility, compatibility includes physical connection, communication protocol, control timing, electrical parameter matching, control logic, security protection strategy." Solve the problem of these key points in order to achieve compatibility. ”
Liu Yongdong told reporters that the 2015 version of the standard backwards is compatible with the 2011 version of the standard by means of software identification, and there are a large number of identification errors; forward compatibility does not reserve a complete software identification machine, resulting in subsequent versions of the difficult to smooth upgrade.
Liu Yongdong said: "ChaoJi charging technology has been jointly developed by the industry in the past 5 years, international cooperation, as well as demonstration project construction and a large number of tests and verification, with standardization and industrialization conditions. ”
In June 2020, the China Electricity Council, the State Grid Corporation, CHAdeMO Agreement and Tokyo Electric Power Holding Co., Ltd. co-sponsored the Sino-Japanese joint conference on the new generation of electric vehicle charging technology held in Beijing, and the new generation ChaoJi charging technology white paper was released at the same time as the CHAdeMO3.0 standard. It is understood that the new generation of ChaoJi charging technology route originated from the high-power charging needs of electric vehicles, is a complete set of electric vehicle DC charging system solutions, to solve a series of defects and problems in the existing charging system in the world, in the charging safety, charging power, structural design, forward compatibility and future-oriented applications have been comprehensively improved. Some industry insiders pointed out that the birth of ChaoJi charging technology provides a unified, safe, reliable and low-cost charging system solution for the world.
The current real vehicle test results show that the maximum charging current of ChaoJi charging technology can reach 360A, and the future goal is to charge up to 900kW, and it takes only 5 minutes to make the vehicle travel 400km. At the same time, due to the compact design and scalability of ChaoJi charging technology, it can be applied to small and medium-power application scenarios, covering the mainstream passenger car field at the same time, but also taking into account the special requirements of heavy-duty vehicles and light vehicles, greatly expanding its application scope.
Text: Wan Renmei Editor: Pang Guoxia Layout: Liu Xiaoye