ISO 15118 - High-level communication

An extended communication scheme is defined in ISO 15118. It offers a flexible communication channel for transmitting more information between the vehicle and the charging station compared to IEC 61851 communication. It therefore enables advanced functions for charging stations, such as:

Plug & Charge: The vehicle can authenticate itself and start the charging process without the need for additional user authentication. This simplifies the user experience, as the vehicle handles the payment and billing processes automatically.
Bi-directional charging: The standard supports vehicle-to-grid (V2G) communication, which enables not only the charging of the electric vehicle, but also the discharging of the vehicle battery into the grid. This can help to balance demand on the electrical grid.
Intelligent charging: This includes the ability of the charging station and vehicle to exchange information about the state of charge, battery condition and grid requirements to optimize charging schedules, electricity rates and power distribution.
Security: ISO 15118 contains provisions for secure communication between the vehicle and the charging infrastructure to protect against unauthorized access and data misuse.

Communication stack ISO 15118

To enable extended functions compared to low-level communication, ISO 15118 uses communication via powerline communication (PLC) between EVSE and EV (Figure 2). Physically, the same CP connection is used as for IEC 61851 communication. However, to enable higher communication data rates, the PLC data stream is modulated to the PWM signal. As far as the higher communication layers are concerned, a Transmission Control Protocol / Internet Protocol (TCP/IP) stack is used for communication.

In conjunction with the EL6761 EtherCAT Terminal, high-level communication can be used to obtain information about the current state of the vehicle, e.g. the current SoC (State of Charge), the remaining charging time, etc., and to enable DC charging.