The Combined Charging System (CCS) is a widely adopted charging standard for electric vehicles (EVs) that integrates both AC (Alternating Current) and DC (Direct Current) charging within a single connector. Introduced in 2011, the CCS standard combines the traditional AC charging plug with two additional DC power pins, allowing for high-power DC fast charging. This dual-functionality design eliminates the need for separate connectors for AC and DC charging. CCS supports charging power levels ranging from standard AC home charging to ultra-fast DC charging significantly reducing charging times for modern EVs. 

CCS is recognized by major automotive manufacturers, including Volkswagen, BMW, Ford, General Motors, and Hyundai, and is increasingly becoming the dominant standard in Europe and North America. The standard is regulated by the CharIN (Charging Interface Initiative) organization, which ensures interoperability and continuous improvements.

Components of the CCS Standard

Connector Types

CCS Type 1: Type 1 is used mainly in North America, South Korea, and parts of Asia. It combines the Type 1 AC connector (single-phase) with two additional DC pins for fast charging. For AC charging, it supports single-phase charging with a capacity of up to 7.4 kW at 240 V, making it suitable for residential setups where single-phase power grids are common. This allows EV owners to conveniently charge their vehicles overnight at home. In contrast, the DC fast charging capability of CCS Type 1 is significantly more powerful, delivering up to 500 A and 1,000 V, which translates to charging speeds of up to 350 kW or even higher in advanced applications. This high-power DC charging dramatically reduces charging time compared to AC charging, making it ideal for public fast-charging stations, especially along highways where quick charging is essential for long-distance travel.

CCS Type 2: It is predominant in Europe, India, and Australia. It incorporates the Type 2 AC connector (three-phase) with the same two DC pins. For AC charging, it supports three-phase charging with a capacity of up to 43 kW at 400 V, making it ideal for both residential and commercial installations where faster AC charging is required. This allows for significantly reduced charging times compared to single-phase systems, benefiting EV owners in regions with advanced electrical grids. Also, the DC fast charging capability of CCS Type 2 is highly efficient, supporting power delivery of up to 500 A and 1,000 V, enabling charging speeds that exceed 350 kW. This ultra-fast charging capability is perfect for high-speed charging networks such as IONITY in Europe, where quick turnaround times are essential for long-distance EV travel and reducing charging station congestion.

Communication Protocols in the Combined Charging System (CCS)

The Combined Charging System (CCS) is not just about delivering power, it also relies on sophisticated communication protocols to secure safe, efficient, and smart charging. These protocols enable real-time data exchange between the electric vehicle (EV), the charging station, and even the power grid. The main communication protocols used in CCS are Power Line Communication (PLC), Controller Area Network (CAN), and Pulse Width Modulation (PWM). Each plays a unique role in the charging process, from basic safety checks to advanced smart grid integration.

Power Line Communication (PLC)

Power Line Communication (PLC) is the primary communication method for CCS, especially for DC fast charging. It allows data to be transmitted over the same power cables used for charging, eliminating the need for additional communication wires. CCS uses HomePlug Green PHY (HPGP), a variant of PLC, which is optimized for low power consumption and high reliability.

Power Line Communication (PLC) facilitates key functions such as authentication and authorization for secure payment transactions, Plug-and-Charge (PnC) for automated billing without RFID cards or apps, smart charging to dynamically adjust power based on grid demand, and Vehicle-to-Grid (V2G) support for bi-directional energy flow to stabilize the grid. The advantages of PLC include seamless integration of advanced features like smart charging and V2G without extra wiring, high data security through encryption protocols, and future-proofing with compliance to the ISO/IEC 15118 which supports evolving smart grid technologies.

Controller Area Network (CAN): The Controller Area Network (CAN) protocol is widely used in the automotive industry for real-time communication between electronic control units (ECUs) within a vehicle. In the context of CCS, CAN is primarily used for low-level communication during the charging process, especially in AC charging scenarios and some basic DC charging systems.

The Controller Area Network (CAN) protocol in the Combined Charging System (CCS) facilitates reliable, real-time communication between the EV’s Battery Management System (BMS) and the charging station. It handles critical functions such as battery management communication, exchanging data on battery temperature, state of charge (SoC), and charging limits; fault detection to quickly identify and report abnormalities for safe charging; and real-time monitoring with low latency to ensure continuous oversight of charging status. The key advantages of CAN include high reliability for robust, error-free communication, low latency for rapid safety responses, and cost-effectiveness due to its simple implementation with minimal hardware requirements.

Pulse Width Modulation (PWM): Pulse Width Modulation (PWM) is a simpler form of communication used primarily for basic signaling between the EV and the charging station during the initial connection phase. It operates over the Control Pilot (CP) line in the charging cable. It is used to manage basic communication between the electric vehicle (EV) and the charging station. It helps verify the connection to ensure the EV is properly connected before charging begins. PWM also controls the charging current by communicating the maximum current available from the charging station, allowing the EV’s onboard charger to adjust accordingly. Also, it performs important safety checks to confirm proper grounding and detect any electrical faults before power is delivered.

The advantages of PWM are that it is simple and reliable, requiring minimal hardware to function effectively. It provides a fast response, offering instant feedback on the connection status and basic power control. PWM is also universally compatible, making it suitable for use across different charging standards, including CCS, Type 1, and Type 2 connectors.

How These Protocols Work Together in CCS

Initial Connection Phase:
When an EV is plugged in, PWM is used over the Control Pilot (CP) line to establish a basic connection, verify safety conditions, and communicate the charger’s current capabilities.

Authentication and Setup:
For DC fast charging, the system transitions to PLC, enabling secure authentication (via Plug-and-Charge) and setting up advanced charging parameters. CAN may be used in parallel for internal vehicle diagnostics and real-time monitoring.

Active Charging Phase:
During charging, PLC handles dynamic communication for smart charging, adjusting power levels based on grid demands. CAN continues to monitor the vehicle’s battery health, temperature, and charging efficiency.

Termination Phase:
 Once charging is complete, the protocols ensure safe disconnection, proper billing, and data logging for future analysis.

 Power Delivery Specifications

The Combined Charging System (CCS) supports both AC and DC charging, catering to different needs. AC charging offers up to 43 kW at 400 V (3-phase) or 240 V (1-phase) with currents up to 63 A, typically taking 4-8 hours for a full charge making it ideal for home, workplace, and urban public chargers. In contrast, DC fast charging with CCS 2.0 delivers over 350 kW at up to 1,000 V and 500 A, enabling a full charge in just 15-30 minutes which makes it optimal for highways and long trips. AC power is converted to DC inside the car, while DC fast charging supplies power directly to the battery for faster charging.

Key Features and Advantages of CCS

Universal Compatibility: CCS provides a standardized interface that reduces fragmentation in the EV market. It supports vehicles from a wide range of manufacturers, enabling EV owners to charge at diverse stations without compatibility issues.

Scalability and Future-Proofing: CCS is designed to accommodate future technological advancements. Its ability to support higher voltages (up to 1000 V) and currents (up to 500 A) ensures compatibility with next-generation EVs, including heavy-duty trucks and commercial vehicles.

High Power & Ultra-Fast Charging: With ultra-fast charging capabilities exceeding 350 kW, CCS minimizes charging times, making EVs more practical for long-distance travel. This is particularly beneficial for public charging stations along highways and high-traffic routes.

Integration with Renewable Energy and V2G: CCS’s support for Vehicle-to-Grid (V2G) technology enables EVs to function as mobile energy storage units. This integration helps stabilize power grids, particularly when combined with renewable energy sources like solar and wind.

Disadvantages of CCS

Complex Connector Design: The CCS connector is larger and bulkier compared to simpler AC-only connectors, making it less usable, especially for everyday residential use. Its dual-purpose design, combining AC and DC pins, adds complexity, which can lead to durability issues over time.

High Infrastructure Costs: DC fast charging stations that support CCS require expensive hardware, grid connections, and advanced cooling systems, which significantly increase installation and maintenance costs. Moreover, upgrading existing AC charging infrastructure to support high-power CCS DC charging can be costly for businesses and municipalities.

Charging Speed Variability: Although CCS supports ultra-fast charging (350 kW+), not all EVs can take full advantage of these speeds due to limitations in their battery management systems and onboard chargers. Charging speeds also decrease significantly as the battery approaches full capacity, which can be frustrating for drivers during long trips.

Compatibility Challenges: Despite its goal of standardization, CCS still has a regional split between CCS Type 1 (common in North America) and CCS Type 2 (widely used in Europe), leading to compatibility issues when traveling internationally. Moreover, some older EV models do not support CCS, requiring adapters or separate charging solutions.

Future of CCS

CCS 3.0 and Beyond: Research is underway to push CCS charging power beyond 500 kW, reducing charging times to under 5 minutes for some vehicles.

Wireless Charging Integration: Efforts are being made to integrate CCS protocols with emerging wireless charging technologies.

Global Standardization: As EV adoption increases, CCS could become the de facto global charging standard, reducing reliance on regional systems.

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