Clear Definition
ISO 15118-20 is the second-generation communication standard for EV-to-charging-station communication. It is part of the ISO 15118 series and defines advanced communication requirements between EVCC and SECC.
Compared with ISO 15118-2, ISO 15118-20 is designed for more advanced charging functions, including bidirectional power transfer, advanced control modes, improved communication structure, and future V2G applications. ISO’s public abstract states that ISO 15118-20 defines communication messages and sequence requirements for bidirectional power transfer between EV and EVSE.
Application Scenarios
ISO 15118-20 is suitable for:
Application Description
V2G charging Vehicle sends power back to grid
V2H charging Vehicle supplies power to home
V2B charging Vehicle supports building energy management
Smart charging Dynamic charging control based on grid or energy needs
Future AC / DC chargers Advanced communication for new-generation EVSE
Technical Flow
A simplified ISO 15118-20 process may include:
EV plugs into EVSE.
EVCC and SECC establish communication.
Network and application layer communication starts.
EV and EVSE negotiate supported services.
Authentication is completed through EIM or Plug & Charge.
EV and EVSE exchange power transfer parameters.
Charging or discharging mode is selected.
Dynamic control is performed during the session.
Session ends with safe shutdown and reporting.
Product Relationship Diagram
Grid / Energy Management System
|
v
Charging Station Power System
|
v
SECC with ISO 15118-20
|
| Advanced V2G communication
v
EVCC with ISO 15118-20
|
v
EV Battery / BMS
ISO 15118-2 vs ISO 15118-20
Item ISO 15118-2 ISO 15118-20
Generation First-generation application layer Second-generation communication
Main use Plug & Charge, smart charging Advanced V2G, bidirectional power transfer
Charging type AC and DC AC, DC, advanced services
V2G capability Limited Stronger and more complete
Project complexity Medium Higher
Hardware requirement Lower than ISO 15118-20 Usually higher computing and security requirements
Standard Protocol Explanation
ISO 15118-20 is not just a simple software upgrade from DIN 70121 or ISO 15118-2. It may involve:
Updated communication stack
More complex message handling
Stronger security requirements
Advanced charging service negotiation
Bidirectional power transfer logic
EVCC, SECC, EVSE controller, and backend coordination
FAQ
Q1: Is ISO 15118-20 the same as Plug & Charge?
No. Plug & Charge is one important function in the ISO 15118 ecosystem, while ISO 15118-20 is a broader second-generation communication standard.
Q2: Can old SECC hardware support ISO 15118-20 by software upgrade?
Not always. ISO 15118-20 may require higher hardware resources, updated security design, and new protocol stack development.
Q3: Is ISO 15118-20 required for all chargers now?
It depends on the target market, charger type, project requirement, and certification plan.
Share Charging Project Capability
Share Charging can support ISO 15118-20 project evaluation for AC and DC charging systems. For customers planning next-generation charging products, we can help confirm:
Whether ISO 15118-20 is required
AC or DC application scope
Plug & Charge requirement
V2G / BPT function requirement
SECC hardware suitability
EVSE controller integration
Testing and certification preparation
