Detailed explanation of the world's major electric vehicle charging connector standards

It is obvious that new energy vehicles dominated by pure electricity have become the general trend of the automobile industry. However, under the current situation that battery technology is difficult to make a breakthrough in a short time, electric vehicles have widely distributed charging facilities, hoping to solve the worries of car owners through sufficient charging equipment. The charging connector of electric vehicle, as a crucial component in the charging equipment, has been faced with direct conflict because of different standards in various countries. Here we would like to sort out the standards of various electric vehicle charging connectors in the world.

Combo

Combo socket can allow slow charging and fast charging of electric vehicles. It is the most widely used socket type in Europe at present, including Audi, BMW, Chrysler, Daimler, Ford, General Motors, Porsche and Volkswagen, all equipped with the charging interface developed by SAE.

On October 2, 2012, the revised SAE J1772 draft voted by the members of the relevant SAE committees became the only official DC charging standard in the world. The core of the standard on DC fast charging based on J1772 revision is Combo Connector.

The previous version of this standard (formulated in 2010) defined the specifications of the basic J1772 connector for AC charging, which has a low charging level (AC Level 1 for 120V, Level 2 for 240V). This basic connector has been widely used today, and is compatible with Nissan LEAF, Chevrolet Volta and Mitsubishi i-MiEV electric vehicles. In addition to all the original functions, the Combo Connector in the new J1772 standard developed in 2012 has two more pins, which can be used for DC fast charging, but is not compatible with the old electric vehicles currently produced.

Advantages: The biggest advantage of Combo Connector is that in the future, automobile manufacturers can use a socket on their new models, which is not only applicable to the first generation of smaller basic AC connectors, but also applicable to the second generation of larger Combo Connector, which can provide DC and AC currents, charging at two different speeds.

Disadvantages: In the fast charging mode, the charging station is required to provide a maximum voltage of 500 volts and a current of 200 amperes.

Tesla

Tesla Motors has its own charging standard, which claims to be able to charge more than 300 kilometers in 30 minutes. Therefore, the maximum capacity of the charging socket can reach 120kw and the maximum current can reach 80A.

At present, Tesla has 908 super charging stations in the United States. In order to enter China, Tesla has also established 7 super charging stations in China, including 3 in Shanghai, 2 in Beijing, 1 in Hangzhou and 1 in Shenzhen. In addition, in order to better integrate into various regions, Tesla plans to give up the control of charging standards and adopt national standards, which have been implemented in China.

Then the problem comes. Although Tesla's favorable effect is that Tesla owners can use the huge charging network established by the Chinese government to charge; Tesla increased product sales. The problem is how to charge the car owners who have purchased Tesla models after the standard changes. If there is no corresponding solution. The contradictions faced by Tesla owners are: First, charging can only be done in charging stations built before the standard changes, and charging convenience will not be improved over time; Second, find Tesla to return the car.

Advantages: advanced technology, high charging efficiency.

Disadvantages: Contrary to national standards, it is difficult to improve sales without compromise; After compromise, the charging efficiency will be reduced, and it will be in a dilemma.

CCS

In order to change the chaotic status quo of charging interface standards, eight major American and German manufacturers, Ford, General Motors, Chrysler, Audi, BMW, Mercedes Benz, Volkswagen and Porsche, released the "Joint Charging System" in 2012. "Combined Charging System" is the "CCS" standard.

The "combined charging system" can unify all current charging interfaces, so that one interface can complete four modes of single-phase AC charging, fast three-phase AC charging, household DC charging and overspeed DC charging.

AE has selected the joint charging system as its standard. In addition to SAE, the European Automobile Manufacturers Association (ACEA) has also announced that it has selected the joint charging system as the DC/AC charging interface for all plug-in electric vehicles sold in Europe since 2017. Since Germany and China unified the charging standard of electric vehicles last year, China has also joined the European and American teams, bringing unprecedented opportunities for the development of electric vehicles in China. Zeno1E, Audi A3e-tron, BAIC E150EV, BMW i3, Denza, Volkswagen e-up, Changan Escape EV and SmartEV all belong to the "CCS" standard camp.

Advantages: BMW, Daimler and Volkswagen, the three German automobile manufacturers, will increase their investment in electric vehicles in China, and CCS standards may be more beneficial to China.

Disadvantages: Electric vehicles that support the "CCS" standard either have a small sales volume or have just started to sell.

CHAdeMO

CHAdeMO is the abbreviation of CHARGE de Move. It is a CHAdeMO socket supported by Nissan and Mitsubishi Motors. CHAdeMO, translated from Japanese, means "charging time is as short as tea break". The DC fast charging socket can provide a maximum charging capacity of 50kw.

The electric vehicle models supporting this charging standard include: Nissan LEAF, Mitsubishi Outlander Plug in Hybrid, Citroen C-ZERO, Peugeot iON, Citroen Berlingo, Peugeot Partner, Mitsubishi i-MiEV, Mitsubishi MINICAB MiEV, Mitsubishi MINICAB MiEV truck, Honda Feidu electric version, Mazda DEMIOEV, Subaru Stella Plug in Hybrid, Nissan eEV200, etc. It should be noted here that Nissan LEAF and Mitsubishi i-MiEV have two different charging sockets, one of which is applicable to the basic J1772 connector, which is the Combo connector introduced in Part I; The other is the CHADEMO standard connector applicable to Japan.

The quick charging mode adopted by CHAdeMO is shown in the figure. The current is controlled by the CAN bus signal of the car. That is, while monitoring the battery status, the current value required for charging is calculated in real time, and a notification is sent to the charger through the communication line; The fast charger receives the current command from the car in time and provides current according to the specified value.

The battery management system monitors the battery condition while controlling the current in real time, fully realizing various functions required for fast and safe charging, and ensuring that charging is not limited by battery universality. In Japan, 1154 fast chargers installed according to the CHAdeMO standard have been put into use. In the United States, CHAdeMO charging stations have also been widely "netting". The latest data from the U.S. Department of Energy shows that there are 1344 CHAdeMO AC fast charging stations in the United States.

Advantages: In addition to the data control line, CHAdeMO also uses the CAN bus as the communication interface. Because of its superior noise resistance and high error detection capability, it has high communication stability and reliability. Its good charging safety record has been affirmed by the industry.

Disadvantages: CHAdeMO's original design of charging output power is 100kW, and the connector is very cumbersome, but the output power of the charging car is only 50kW.

GB/T20234

In 2006, China issued the General Requirements for Plugs, Sockets, Vehicle Couplers and Vehicle Sockets for Conductive Charging of Electric Vehicles (GB/T20234-2006), which specifies the connection classification methods for charging current of 16A, 32A, 250A AC and 400A DC in detail. It mainly refers to the standards proposed by the International Electrotechnical Commission (IEC) in 2003, but this standard does not specify the number of connection pins of charging interfaces Physical dimensions and interface definitions. In 2011, China also introduced the GB/T20234-2011 recommended standard, which replaced part of the contents in GB/T20234-2006, which stipulates that the AC rated voltage shall not exceed 690V, the frequency shall be 50Hz, and the rated current shall not exceed 250A; The DC rated voltage shall not exceed 1000V, and the rated current shall not exceed 400A.

Advantages: Compared with the 2006 version of the national standard, more charging interface parameters are calibrated in detail.

Disadvantages: The standard is still not perfect. In addition, they are only recommendatory standards and are not enforced.

New generation ChaoJi charging system

In 2020, the China Electricity Council and the CHAdeMO Agreement will jointly launch the research on the development path of ChaoJi's industrialization, and issue the White Paper on Electric Vehicle ChaoJi Conductive Charging Technology and the CHAdeMO3.0 standard respectively.

The ChaoJi charging system is forward compatible and backward compatible. A new control and guidance circuit scheme is developed, and the hard node signal design is added. When a fault occurs, the signal is used to quickly notify the opposite end to make a quick response in time to ensure charging safety. Establish the safety model of the whole system, optimize the insulation monitoring performance, and define a series of safety problems such as I2t, y capacitance, PE conductor selection, maximum short-circuit capacity, PE wire breakage, etc. At the same time, the thermal management system has been re evaluated and re designed, and a test method for the charging connection device has been proposed.

The ChaoJi charging interface adopts a 7-pin end face design scheme, with a voltage level of 1000 (1500) V and a maximum current of 600A. The design of ChaoJi charging interface reduces the overall size, optimizes the fit tolerance, reduces the power terminal size, and meets the IPXXB safety requirements. At the same time, the plug and pull physical guidance is designed to deepen the insertion depth of the front end guidance of the socket, which meets the requirements of human engineering.

The ChaoJi charging system does not simply refer to the high-power charging interface. It is a systematic DC charging solution for electric vehicles, including the design and compatibility of control and guidance circuits, communication protocols, connecting devices, the safety of the charging system, and thermal management under high-power conditions. ChaoJi charging system is a unified scheme facing the world, so that the same electric vehicle can be applied to the charging system of corresponding countries in different countries.

summary

Due to the difference of brands, the applicable charging equipment standards of new energy vehicles on the market are not the same. A single type of charging connector structure cannot meet all vehicle models. In addition, the technology in the field of new energy vehicles is still in the process of maturing. Many automotive manufacturers' charging posts and charging connection systems are still faced with problems such as unstable product design, potential safety hazards, abnormal charging, incompatible vehicle posts, and lack of testing standards in practical applications, environmental aging, etc.

Nowadays, automobile enterprises all over the world have gradually realized that "standard" is the key factor to control the development prospect of electric vehicles. In recent years, the global charging standards have gradually moved from "diversification" to "centralization". However, in order to truly realize the unification of charging standards, in addition to interface standards, current communication standards are also required. The former is related to whether the connectors are matched, and the latter affects whether the plug can be powered when inserted. The unification of charging standards for electric vehicles still has a long way to go, and car enterprises and governments of all countries need to further "open their minds", so that electric vehicles can have a future.