The General Administration of Quality Supervision, Inspection and Quarantine, the State Standards Commission, together with the National Energy Administration, the Ministry of Industry and Information Technology, the Ministry of Science and Technology and other departments, released five newly revised national standards for electric vehicle charging interfaces and communication protocols in Beijing.
China promulgated its own four national standards for electric vehicle charging interfaces and communication protocols on December 22, 2011. However, the charging current, voltage, power and other details have not been further made detailed requirements. The revision of the 5 standards for electric vehicle charging interfaces finally achieves unity in hardware and software, comprehensively improving the safety and compatibility of charging. This article will make a detailed interpretation of the new national standard.
Charging interface standards have been revised several times
In 2006, China issued the General Requirements for Plugs, Receptacles, Vehicle couplers and Vehicle jacks for Conductive Charging of Electric Vehicles (GB/T20234-2006). This national standard detailed the connection classification of 16A, 32A, 250A AC and 400A DC charging current. It mainly refers to the standard proposed by the International Electrotechnical Commission (IEC) in 2003, but this standard does not specify the number of pins, physical size and interface definition of the charging interface. In 2011, China introduced the GB/T20234-2011 recommended standard, replacing part of GB/T20234-2006, which stipulates: rated AC voltage shall not exceed 690V, frequency 50Hz, rated current shall not exceed 250A; The rated DC voltage does not exceed 1000V and the rated current does not exceed 400A.
The new national standard charging interface standard has improved the voltage and current levels, and adjusted the size of the signal needle and part of the mechanical lock, and clarified the relevant requirements of the electronic lock.
On the other hand, the new standard is of great benefit to the charging equipment, and it is of great help to the promotion and application of the charging equipment. Before the charging equipment faced with the problem of "who builds who uses", the national standard focused on the unification of the charging pile communication protocol, which means that the electric vehicle charging interface in the standard level of hardware and software finally realized unity, which will improve the utilization rate of charging equipment.
What are the changes of the new national standard
Compared with the old standard, there are many changes in the new standard, some of which are optimized in details. For example, this revision of the charging interface standard raises the voltage and current levels, thus increasing the charging power and shortening the charging time, and also adjusts the size of part of the signal needle and mechanical lock, and optimizes the connection timing.
1. General requirements
The new national standard requires the installation of electronic lock in the DC charging gun, while reserving the vehicle socket with the mechanical structure of electronic lock. The implementation plan will be completed by the charging pile enterprise, and the automobile enterprise may add the control guidance circuit.
According to the new national standard, when the AC charging current is greater than 16A, the power supply opening and vehicle interface should have the locking function, and the locking function should meet the relevant requirements of GB/T20234.1-2015. Power supply sockets and vehicle sockets should be equipped with electronic locking devices to prevent accidental disconnection during charging. When the electronic lock is not reliably locked, the power supply device or electric vehicle should stop charging or do not start charging.
During DC charging, the vehicle interface shall have the locking function, which shall meet the relevant requirements of GB/T20234.1-2015. The vehicle plug should be equipped with a mechanical locking device, and the power supply equipment should be able to judge whether the mechanical lock is reliable. The vehicle plug should be installed with an electronic locking device. When the electronic lock is in the locking position, the mechanical lock should not be able to operate. The power supply system should be able to judge whether the electronic lock is reliably locked. When the electronic lock is not reliably locked, the power supply device or electric vehicle should stop charging or not start charging.
At the same time, the electronic locking device should have emergency unlocking function, should not be live lock and should not be unlocked by direct manual operation.
In addition, the general requirements also specify the functional description of the power supply interface and vehicle interface, interface temperature monitoring, god current protector, overload and short circuit protection of the power supply equipment, charging emergency stop, maintenance of the power supply equipment and other requirements.
2. Refinement of communication protocols
While previous standards specified the definitions of different signals in detail, the new standard not only defines the definitions, but also specifies the transmission rate in various states, the determination of the timeout of the message, the determination of the maximum current output, and also specifies the fault and the termination of the message sending.
In the new standard, the communication rate between the motor and the BMS is clearly specified, while in the old standard, there is no limit, only the recommended value is mentioned. According to the standard, the communication rate of 50kbit/s can be adopted in special situations with poor communication environment (such as commercial vehicle charging war with long communication distance) after the agreement of power supply equipment manufacturers and electric vehicle manufacturers.
Packet options are classified into mandatory and optional items. If all contents in a packet are optional, the packet can be selected not to be sent. If some contents in a packet are optional, the packet can be sent or filled with 1 in the format specified in the standard. Padding 1 for bits not specified by the standard or reserved bits.
BRM adds 8 bytes for reservation, CML adds the minimum charge current field, CCS adds the charge pause field, and BMS adds the cause of charge stop fault. In addition, it also adds the charging sequence flow chart, the troubleshooting method of the charging process, and the start and stop conditions of the message.
3. Modification of charging interface
According to the introduction, this revision focuses on the safety and compatibility of charging, adding charging temperature monitoring, mechanical lock and electronic lock linkage, overload and short circuit protection and other safety measures, improve the guidance and timing of charging control, fault classification information, redundancy protection and other contents, improve the adaptability and operability of the standard.
3.1 AC charging interface
The rated current of the AC connector used for conduction charging of electric vehicles has been changed from 32A to 63A. If the power supply interface uses a standardized plug socket conforming to GB2099.1 and GB1002, these plug sockets are not applicable.
The rated current value of the charging port is increased by 10A and 63A. As shown in the picture:

The standby contacts are extended for three-phase charging. As shown in the picture:

Add R4 resistance in the charging connection interface, as shown in the figure:

In addition, the revised standard deletes the control guide circuit and control principle, modifies part of the dimensions of the charging interface control guide contact and mechanical lock, adds the drainage hole in the socket (optional), changes the sealing ring seal to optional, and modifies the space dimension requirements of the plug.
3.2 DC charging interface
Modified the maximum rated voltage of the charging port. The rated voltage does not exceed 100V (DC) and the rated current does not exceed 250A (DC).
The rated voltage of charging interface 80A and 200A is increased, as shown in the figure:

The contact coupling sequence in the process of charging connection is adjusted, which is as follows: protection grounding, charging connection confirmation (CC2), DC power and DC power negative, low voltage auxiliary power and low voltage auxiliary power, charging communication, charging connection confirmation (CC1); In the process of disengagement, the order is reversed.
In addition, the new national standard has deleted the guidance circuit and control principle of DC charging control in charging mode 4; Modified some dimensions of the charge interface control guide contact and mechanical lock; The dimensions of the plug-in space have been modified.
Certification and testing of charging standards
Tian Shihong, head of the National Standards Commission, said the new standards ensure interconnection between electric vehicles and charging facilities, avoid disorderly market development and charging "islands", and help reduce the waste of social resources caused by incompatibilities. Going forward, the General Administration of Quality Supervision, Inspection and Quarantine and the State Standards Commission, together with relevant industry departments, will promote the use of the new standard in the certification and access management system of charging facilities, and encourage charging facilities and electric vehicle manufacturers to organize production according to the new standard. Charging facilities already built and under construction should be updated and upgraded according to the new standard. At the same time, the National Standards Commission will strengthen the formulation of supporting standards such as interoperability testing of charging facilities, safety prevention of charging stations and operation services, so as to provide technical support for management, operation and maintenance of charging facilities.
However, at present, and the previous national standard is the same, testing certification is voluntary behavior, not mandatory.

Zheng Zhijie, deputy director of the National Energy Administration, revealed that in the next step, the National Energy Administration will speed up the construction of charging infrastructure, further regulate the access of the charging infrastructure industry, and take meeting the new national standards as one of the conditions for charging infrastructure market access.
Application and transformation aspect
In terms of interface standards, there are four international DC charging technical solutions, namely European standard, American standard, Japanese standard and Chinese standard. In terms of implementation, Chinese charging piles will not be compatible with other standards. The products of foreign enterprises need to be improved to meet Chinese standards in the Chinese market.
On the issue of how to deal with electric vehicles and charging stations that have been built and sold after the new standard is implemented, an official from the commission said, "There is no problem of compatibility between the old and new standards for private cars that charge at individual charging stations, and charging facilities and vehicles that charge buses and taxis on fixed lines. Among the charging piles that have been built, the ones facing renovation are mainly public ones."
It is worth noting that since the charging interface also includes one end of the electric vehicle, so the electric vehicle also needs to be adjusted. According to the new national standard, the electric vehicle must be reformed not only the communication protocol on the software, but also the control guidance circuit on the hardware. Therefore, if the owner needs to use the public charging pile in the future, the vehicle needs to be upgraded. If the private charging pile can meet the daily demand of the vehicle, the owner can also choose not to transform the vehicle