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

2021-06-15 16:00:32  Resource

It is clear that new energy vehicles, mainly purely electric, have become a major trend in the automotive industry. However, the current situation of electric vehicles is difficult to make a breakthrough in battery technology in a short period of time, the extensive layout of charging facilities, hoping to solve the worries of car owners through adequate charging equipment. The electric vehicle charging connector, as a crucial component in the charging equipment, has been facing a direct conflict situation because of the different standards in different countries. Here we take a look at the various EV charging connector standards around the world.


Combo


The Combo socket allows for both slow and fast charging of electric vehicles and is currently the most widely used socket type in Europe, with Audi, BMW, Chrysler, Daimler, Ford, GM, Porsche and Volkswagen all configured with charging interfaces developed by SAE (Society of Automotive Engineers).


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


The previous version of the standard (developed in 2010) specified a basic J1772 connector for AC charging at a lower level (AC Level 1 for 120V and Level 2 for 240V). This basic connector is widely used today and is compatible with the Nissan LEAF, Chevrolet Volt and Mitsubishi i-MiEV electric vehicles. The new version of the J1772 standard developed in 2012, on the other hand, has all the features of the original Combo Connector with two additional pins for DC fast charging, but it is not compatible with older EVs currently in production.


Pros: The big advantage of the Combo Connector is that future car manufacturers will be able to adopt a socket on their new models, not only for the smaller sized basic AC connector of the first generation, but also for the larger sized Combo Connector of the second generation, which can provide both DC and AC currents, charging at two different speeds respectively.


Disadvantage: fast charging mode requires a maximum voltage of 500 volts and a current of 200 amps from the charging station.


Tesla


Tesla cars have their own charging standard and claim to be able to charge up to 300 km in 30 minutes. This is why its charging sockets can have a maximum capacity of 120kw and a maximum current of 80A.


At present, Tesla has 908 Superchargers in the USA. In order to enter China, Tesla has also set up seven Superchargers in China: three in Shanghai, two in Beijing, one in Hangzhou and one in Shenzhen. In addition, in order to better integrate into the various regions, Tesla plans to give up control of the charging standards and adopt the national standards of each country, which it has already so implemented in China.


Advantages: advanced technology and high charging efficiency.


Disadvantages: contrary to the national standard of each country, it is difficult to increase sales without compromise; compromise will compromise charging efficiency, in a dilemma.


CCS


In order to change the confusing status quo of charging interface standards, the eight major American and German manufacturers Ford, GM, Chrysler, Audi, BMW, Mercedes-Benz, Volkswagen and Porsche released the "Combined Charging System" (CCS) in 2012. The "Combined Charging System", or "CCS", is a standard.


"CCS unifies all existing charging interfaces so that one interface can be used for all four modes: single-phase AC charging, fast three-phase AC charging, domestic DC charging and super-speed DC charging.


AE has selected the combined charging system as its standard and, in addition to SAE, the European Automobile Manufacturers' Association (ACEA) has announced its selection of the combined charging system as the DC/AC charging interface for all plug-in electric vehicles sold in Europe from 2017 onwards. Since the harmonisation of EV charging standards between Germany and China last year, China has joined this European and American camp, presenting unprecedented opportunities for the development of electric vehicles in China. The Zeno 1E, Audi A3 e-tron, BAIC E150EV, BMW i3, Tenshi, Volkswagen e-up, Chang'an EV and SmartEV are all in the 'CCS' standard camp.


Pros: BMW, Daimler and Volkswagen are the three German automakers that will increase their commitment to electric vehicles in China, and the CCS standard may be more favourable to China.


Cons: The electric cars that support the CCS standard are either in low volume or just starting to go on sale.


CHAdeMO


CHAdeMO stands for CHArge de Move, and is a CHAdeMO socket supported by Nissan and Mitsubishi Motors in Japan, etc. CHAdeMO translates from Japanese to mean "short charging time like a tea break". This DC fast charging socket can provide a maximum charging capacity of 50kw.


Electric vehicle models that support 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 Fit Electric, Mazda DEMIOEV, Subaru Stella plug-in hybrid, Nissan eEV200, etc. It should be noted here that both the Nissan LEAF and the Mitsubishi i-MiEV EV have two different sockets for charging, one for the basic J1772 connector, the Combo connector described in Part 1, and the other for the local Japanese CHAdeMO standard.


The fast charging method used by CHAdeMO is shown in the diagram and the current is controlled by the vehicle's CAN bus signal. This means that while monitoring the battery status, the current value required for charging is calculated in real time and a notification is sent to the charger via the communication line; the fast charger receives the current command from the car in time and provides the current at the specified value.


By monitoring the battery condition and controlling the current in real time, the battery management system fully realises all the functions required for fast and safe charging, ensuring that charging is not limited by the versatility of the battery. In Japan, 1,154 fast chargers installed in accordance with the CHAdeMO standard are in operation. In the USA, CHAdeMO charging stations are also widely available, with the latest data from the US Department of Energy showing that there are now 1,344 CHAdeMO AC fast charging stations in the USA.


Benefits: In addition to the data control line, CHAdeMO also uses the CAN bus as the communication interface, which has high communication stability and reliability due to its superior noise immunity and high error detection capability. Its good charging safety record has been recognised by the industry.


Disadvantages: CHAdeMO was originally designed for a charging output of 100 kW and the connector is very bulky, but the output in charging vehicles is only 50 kW.


GB/T20234


China released the General Requirements for Plugs, Sockets, Vehicle Couplers and Vehicle Jacks for Conductive Charging of Electric Vehicles (GB/T20234-2006) in 2006. This national standard specifies in detail how to classify the connections for charging currents of 16A, 32A, 250A AC and 400A DC, drawing mainly on the standard proposed by the International Electrotechnical Commission (IEC) in 2003, but this standard does not specify the number of connection pins, physical dimensions and interface definitions for charging interfaces.


In 2011, China also introduced the GB/T20234-2011 recommended standard, replacing some of the content in GB/T20234-2006, which states: AC rated voltage not exceeding 690V, frequency 50Hz, rated current not exceeding 250A; DC rated voltage not exceeding 1000V, rated current not exceeding 400A.


Advantages: More detailed calibration of charging interface parameters compared to the 2006 version of the national standard.


Disadvantages: The standard is still not perfect. In addition, it is only a recommended standard and is not mandatory.


The new generation of ChaoJi charging systems


In 2020 the China Electricity Council and the CHAdeMO protocol will jointly initiate research on the development route of ChaoJi industrialisation and release the White Paper on ChaoJi Conduction Charging Technology for Electric Vehicles and the CHAdeMO 3.0 standard respectively.


The ChaoJi charging system can be forward-compatible and backward-compatible. A new control guidance circuit scheme was developed, adding a hard node signal design to ensure charging safety by using the signal volume to quickly notify the counterpart in time for a quick response when a fault occurs. A safety model for the whole system was established to optimise the insulation monitoring performance and clarify a series of safety issues such as I2t, y capacitance, PE conductor selection, maximum short-circuit capacity and PE disconnection. At the same time, the thermal management system is re-evaluated and redesigned, and a test method for the charging connection device is proposed.


The ChaoJi charging interface uses a 7-pin end face design solution for voltage levels up to 1000 (1500) V and maximum currents up to 600 A. The ChaoJi charging interface has been designed to reduce overall dimensions, optimise mating tolerances, reduce power terminal dimensions and meet IPXXB safety requirements. The design of the physical guide for plugging and unplugging also deepens the front guide insertion depth of the socket to meet ergonomic requirements.


The ChaoJi charging system is not simply a high-power charging interface, it is a systematic solution for DC charging of electric vehicles, including the design and compatibility of control and guidance circuits, communication protocols, connection devices, safety of the charging system, thermal management under high-power conditions, etc. The ChaoJi charging system is a unified solution for the world, so that the same electric vehicle can be used in different countries. The ChaoJi charging system is a unified solution for the world, so that the same electric vehicle can be used in different countries.


Conclusion


Today's new energy vehicles are available in different brands and the charging equipment standards are not the same, so a single type of charging connector structure cannot be used for all models. The technology in the field of new energy vehicles is still in the process of maturing, and the charging piles and charging connection systems of many car manufacturers are still facing problems such as unstable product design, safety hazards, charging anomalies, incompatibility between vehicles and piles, and lack of testing standards in practical applications and environmental ageing.


Nowadays, car companies from all over the world have gradually realised that "standards" are the key factor in the future development of electric vehicles. In recent years, global charging standards have gradually moved from "diversity" to "centralisation". But in order to truly achieve a unified charging standard, in addition to interface standards, current communication standards are also needed, with the former being about whether the connector fits and the latter affecting whether the plug can be energised when inserted. Electric vehicle charging standards are still a long way from being unified, and car companies and governments need to further "liberalise their stance" before electric vehicles can have a future. We look forward to our leading efforts to promote the ChaoJi conductive charging technology standard for electric vehicles to play a greater role in the future.


Luoyang Grasen Power Technology Co., Ltd is a professional AC home charger and DC fast charger EV supercharger manufacturer for 11 years in China, the charging connectors can be any two of CCS1/CCS2/CHAdeMO/GBT. Please enter our website for more information: https://www.grasen.com. Please send email to sales@grasen.com for inquiry.


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