ISO 15118—Communication between Electric car and EV Charger

ISO 15118 communication is a protocol launched by ISO and IEC, aiming to ensure interoperability, smart charging, and a higher safety level.

smart charging

1. Various aspects of ISO 15118 communication

The launched ISO 15118 protocol which has been the international standard is ISO 15117-1,2,3,4,5,8. 6 and 7, which are related to wireless charging, are integrated into 1 and 2.

  • ISO 15118-1 is the general information and use case definition which is based on the application scenario of charging and charging procedure and depicts the interaction between different devices.
  • ISO 15118-2 is the network layer and application layer requirements. The application scenario this part describes defines a message, massage sequences, and state machines as well as the technical requirements to achieve these application scenarios.
  • ISO 15118-3 is about physical and data link layer requirements. It uses Power Line Communication.
  • ISO 15118-4 is about network and application configuration tests.
  • ISO 15118-5 is about physical and data link layer configuration tests.
  • ISO 15118-9 and ISO 15118-10 are about wireless charging.
  • ISO 15118-20 is the newest version of the communication standard for the EV in the future.
  • ISO 15118 is based on client-server mode. The Electric Vehicle Communication Controller sends a requirement, and the supply equipment communication controllers will send back a response. The Electric Vehicle Communication Controller needs to receive the response message within a certain time limit. Otherwise, the conversation will be closed.

2. The difference between ISO 15118 and IEC 61851

IEC 61851 is a safety-related communication protocol based on Pulse Width Modulation.

ISO 15118 enhances the communication mechanism between electric vehicles and electric vehicle chargers through a higher-level digital protocol, providing more abundant information including two-way communication, channel encryption, authentication, authorization, charging status, departure time, etc.

If an electric car charger only complies with IEC 61851, a 5% duty cycle will result in the charger charging at the maximum current without caring about the BMS of the electric car. That is, the charger will not adjust the current depending on the car’s needs.

3. The core function of ISO 15118

Smart charging

Smart charging is the ability to intelligently control, manage, and adjust the charging of an electric car which is based on the real-data communication between the EV, EV charger, Charging point operator, and electricity supplier.

Users can use an application provided by the e-Mobility Service Provider to input requested energy and send it to the CPO’s Charging Station Management System.

Smart charging to enhance charging efficiency
Smart charging to enhance charging efficiency
Plug and Charge

Plug and charge makes it more convenient and safer to charge EVs without any authentication like an APP and RFID card which may have the risk of secret leakage. Any information during the transaction like the EV, charging network, and the bill is well protected. OCPP 2.0.1 offers a standard solution for Plug and Charge.

Plug and Charge


V2G refers to the vehicle to the grid. It helps a lot to balance the grid with the electric car serving as a portable battery to reserve energy during off-peak times and output electricity during peak periods.

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