Understanding front-end protocol support for V2G charging in EVs

A front-end protocol in electric vehicle (EV) charging focuses on the communication between the vehicle and the charging station. The protocol ensures safe and efficient charging, manages data exchange for controlling the charging process, and facilitates smart charging features.

Vehicle-to-grid (V2G) refers to the communication and operational standards that enable EVs to interact with the power grid. Such communication allows the charging of the vehicle’s battery from the grid and the discharging of stored energy back into the grid when needed.

The EV charging and communication can be divided into two parts, known as front-end and back-end protocol, as shown in Figure 1. The front-end involves the interaction between the EV and the charging station. On the other hand, the back-end deals with the communication between the charging station and a central management system or cloud services, including user authentication, billing, and remote monitoring.

Figure 1. Front-end and back-end protocol illustration in an EV charging environment. (Image: Rakesh Kumar, Ph.D.)

The front-end protocol can be divided into five sections, illustrated in Figure 2, namely

Inlet and outlet plug
Charging technologies
Communication
Security
Safety

Several standards fall into each of these sections, which are explained below. Please note that some standards are exclusively meant for a section, while others cover multiple sections.

Figure 2. The different sections of a front-end protocol in EV charging. (Image: Rakesh Kumar, Ph.D.)

1. Inlet and outlet plugs
EV charging standards for plugs, inlets, and outlets are crucial for ensuring compatibility, safety, and efficiency across different vehicles and charging infrastructures. The IEC 62196 -1/2/3 (Figure 3) is the main standard that covers single-phase and three-phase power supply for different regions of the world.

Figure 3. Inlet and outlet plugs section of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

2. Charging technologies
EV charging technologies refer to the different configurations and methods through which EVs are charged, including aspects like the power flow, connection type, and communication protocols between the vehicle and the charging infrastructure. The same is illustrated in Figure 4. The applicable standards include IEC 61851 – 1/21/22/23, IEC 61980 -1/3, and IEC 61439 – 1/7.

Figure 4. Charging technologies section of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

3. Communication
Communication standards for EV charging are necessary for ensuring interoperability, security, and efficiency between EVs and charging stations. These standards cover the exchange of information, such as identification, billing, charging control, and grid integration. Some of the key standards, as shown in Figure 5, are ISO/IEC 15118, IEC 61850, IEC 61851 – 24, IEC 61980 – 2, and IEC 62351.

Figure 5. Communication section of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

4. Security
Security in EV charging involves protecting the communication and data exchange between EVs, charging stations, and the broader network infrastructure from unauthorized access, tampering, and other cyber threats.

Given the increasing connectivity and smart capabilities of EVs and charging systems, security standards such as ISO/IEC 27000, IEC/ISO 15118, IEC 62351, and IEC 61850 (Figure 6) are crucial for ensuring user privacy, data integrity, and system reliability.

Figure 6. Security section of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

5. Safety
Safety standards for EV charging are essential to protect users, vehicles, and the charging infrastructure from electrical hazards, fires, and mechanical risks. These standards encompass the design, installation, operation, and maintenance of EV charging equipment and include guidelines for electrical safety, user interaction, and emergency response.

Figure 7 shows the different standards on safety, such as IEC 62196 -1/2/3, IEC 61851 – 1, IEC 61140, IEC 62040, IEC 60529, IEC 60364-7-722, ISO 6469-3, ISO 17409.

Figure 7. Safety section of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

Figure 8 combines all the different sections and standards into a single frame. It can be observed that each section covers an earlier one, as well as the standards. Also, some sections — such as four and five — emphasize the different sections of specific standards.

Figure 8. Complete sections of the front-end protocol of EV. (Image: Rakesh Kumar, Ph.D.)

Summary
Regarding front-end protocol, even experts are led to believe that it deals only with communication. However, it’s necessary to understand the difference between front-end protocol and front-end communication. The former is a bigger picture of plugs, charging technology, communication, security, and safety. The latter is only one part of the protocol.

By no means is the covered standards in this FAQ an exhaustive list of all standards. Some other standards, such as the CHAdeMO, Combined Charging System (CCS), and North American Charging Standard, also fall into one or another section. However, the standards covered in this FAQ are universally accepted by standards organizations and ready to deploy across most countries.

References