Electric Vehicle Communication Controller (EVCC): Functional Overview
For a better understanding of this article, it is recommended to first read Electric Vehicle Charging Inlet (EVI): Components and Interfaces
As electric vehicles (EVs) continue to expand globally, the need for safe, efficient, and standardized charging becomes increasingly critical. One key component that manages the entire charging process inside the EV is the Electric Vehicle Communication Controller (EVCC).
The EVCC serves as the central brain for handling communication with the charging station, monitoring the connection status, controlling safety features, and ensuring smooth charging operations.
In this article, we will explore the functional overview of EVCC, understand why it is needed, and dive into the various key tasks it performs during an EV’s charging session.
What is an EVCC?
The Electric Vehicle Communication Controller (EVCC) is a critical onboard ECU (Electronic Control Unit) responsible for managing the communication, control, and monitoring tasks during an EV charging session.
It serves as the primary interface between the vehicle and the EVSE (Electric Vehicle Supply Equipment).
Why is an EVCC Needed?
Due to the complexity of modern charging processes—which include authentication, communication negotiation, safety monitoring, and charging coordination—a dedicated controller is necessary to ensure:
- Reliable and standardized communication with the EVSE
- Safe and controlled handling of high-voltage systems
- Monitoring and diagnostics during the charging process
- Compliance with global charging standards (ISO 15118, DIN 70121, CHAdeMO, GB/T, etc.)
A Global Challenge: Different Inlets, One EVCC
One of the major challenges in the EV world is regional diversity in charging standards.
- Europe uses Type 2 and CCS2.
- North America leans on Type 1 and CCS1.
- China has GB/T standards.
- Japan favors CHAdeMO.
Each charging inlet type has its own unique set of high-voltage and low-voltage interfaces, which might suggest designing a separate EVCC for each region.
However, the smarter approach adopted by EV manufacturers is to develop a single, global EVCC capable of supporting all inlet types and their corresponding interfaces.
How does that work?
- The core functionality of EVCC—monitoring and controlling charging—remains exactly the same, regardless of the inlet.
- The EVCC is designed to accommodate all necessary circuits required for different global charging standards, ensuring compatibility with various inlet types used across regions.
- While the EVCC hardware stays common globally, the wiring harness connecting the charging inlet to the EVCC is region-specific, and only the relevant circuits within the EVCC are utilized based on the inlet and wiring configuration.
Functional Overview of EVCC
The primary functions of the EVCC are described below:
1. Charging Cable Connection Detection
The EVCC monitors the inlet interfaces to detect the connection status of a charging cable.
Key detection signals include:
- Proximity Pilot (PP) detection: Based on proximity resistance, it determines whether a charging connector is inserted and if it is properly seated.
Accurate detection is essential to initiate further communication and safety mechanisms.
2. Communication with EVSE
The EVCC is responsible for establishing and maintaining communication with the EVSE.
Depending on the charging standard, the communication methods include:
- PLC (Power Line Communication): Used in standards like CCS (Combined Charging System).
- CAN (Controller Area Network): Used in CHAdeMO and GB/T protocols.
Communication tasks include:
- Authentication and authorization
- Charging session negotiation
- Monitoring power delivery parameters
- Exchanging error or shutdown information
3. Locking Motor Control and Position Monitoring
To ensure the secure connection of the charging cable:
- The EVCC controls the locking actuator motor to lock or unlock the charging connector.
- It monitors position sensors to confirm the lock status (locked/unlocked).
Proper locking ensures that high-voltage charging cannot commence unless mechanical safety is achieved.
4. Charging Status LED Control
The EVCC manages the charging status LED located at or near the charging inlet.
It controls the LED color and blinking pattern based on the charging process stage:
- Waiting for connection
- Active charging
- Charging completed
- Fault detected
This provides immediate visual feedback to the user.
5. Charging Stop Button Monitoring
Some EVs are equipped with a charging stop button located near the inlet.
The EVCC continuously monitors this input:
- If the button is pressed during charging, the EVCC initiates a controlled shutdown sequence to safely stop the charging session.
6. Charging Inlet Temperature Monitoring
High temperatures at the charging inlet or along the high-voltage lines can lead to unsafe conditions.
The EVCC monitors temperatures using sensors:
- It can adjust the charging current or terminate charging if critical temperature thresholds are exceeded.
This feature is critical for preventing connector overheating and possible fire hazards.
7. Wakeup Condition Monitoring
When the vehicle is in a sleep or idle state (low-power mode), the EVCC disables all major operations to minimize 12V battery drain.
However, it continues to monitor specific wakeup conditions, such as:
- Charging cable connection detected
- Communication initiated by EVSE
- Stop button pressed
Upon detecting a valid wakeup event, the EVCC resumes full operation.
8. Communication with Other ECUs
In some vehicle architectures:
- The EVCC acts as a data gateway, relaying measurement and status information to higher-level controllers like the Vehicle Control Unit (VCU) or Battery Management System (BMS).
- In others, the EVCC acts as a primary charging controller, implementing charging control logic internally.
This flexibility allows EV manufacturers to design system architectures suited to their specific requirements.
9. Plug and Charge (PnC) Support
With the move toward seamless charging experiences, many modern EVCCs are designed to support Plug and Charge (PnC) functionality under ISO 15118-2 and ISO 15118-20:
- Upon plug-in, automatic authentication and billing occur without needing manual user input (no apps, no cards).
- EVCC handles certificate-based authentication and secure communication with the EVSE.
Summary
The EVCC plays a central role in enabling safe, efficient, and interoperable EV charging across global markets.
By adopting a common EVCC design and adapting only the wiring harness and inlet interface regionally, manufacturers can streamline vehicle production without compromising on functionality or standards compliance.
Its capabilities in communication, monitoring, control, and safety management make the EVCC one of the key enablers of modern electric vehicle ecosystems.
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