Combined Charging System
The Combined Charging System (CCS) is a conductive charging standard for battery electric vehicles that integrates pins for both alternating current (AC) Level 2 charging and direct current (DC) fast charging within a single connector, promoting interoperability between existing AC infrastructure and higher-power DC systems.[1][2] Developed through collaboration among major automakers including BMW, Daimler, Ford, General Motors, and Volkswagen, CCS originated from efforts initiated in 2010 by SAE International in North America and the European Automobile Manufacturers' Association (ACEA), with formal introduction around 2011 to address fragmentation in EV charging protocols.[3][4] The standard features two main variants: CCS1, which extends the SAE J1772 AC connector with two additional DC pins for the North American market, and CCS2, which builds on the IEC 62196 Type 2 (Mennekes) connector for Europe, Asia-Pacific, and other regions, both enabling DC charging currents up to 500 amperes and voltages supporting power levels of 350 kW or more.[5][6] Administered and promoted by the Charging Interface Initiative (CharIN) e.V., CCS has achieved dominance in European public infrastructure, where it is required by regulation for fast chargers, and was the de facto standard for DC fast charging in North America until recent years.[7][8] However, in 2023–2025, widespread adoption of Tesla's North American Charging Standard (NACS) by legacy automakers—driven by access to Tesla's more reliable and expansive Supercharger network—has prompted a market shift, with many 2025 model-year vehicles incorporating native NACS ports or adapters, underscoring that real-world deployment and ecosystem integration can override initial standardization efforts.[9][10]History
Origins and Standardization (2008–2012)
The Combined Charging System (CCS) emerged from collaborative initiatives among North American and European automakers to address the need for a unified charging interface amid early electric vehicle commercialization. As battery electric vehicles gained traction post-2008 financial crisis recovery, competing proprietary standards risked market fragmentation; Japan's CHAdeMO protocol, developed by Nissan and others for DC fast charging, had gained early momentum with its first specifications outlined by 2009 and association formed in 2010. In contrast, U.S. and European manufacturers prioritized extending established AC connectors—SAE J1772 (revised October 2009 for Levels 1 and 2) and the Mennekes Type 2 (proposed circa 2009)—by integrating DC fast-charging pins, enabling a single connector for both AC up to 19.2 kW and DC up to initial targets of 100 kW. This approach emphasized backward compatibility and cost efficiency over entirely new designs.[11] Standardization efforts formalized in 2011, when SAE tasked a committee with developing the J1772 Combo 1 coupler, adding two DC pins below the AC interface to support power levels exceeding AC limits while reusing existing signaling protocols like pilot control for safety. European counterparts aligned via the VDE Association and IEC 62196 framework, adapting Type 2 (IEC 62196-2, published 2011) into Combo 2 with analogous DC extensions, fostering transatlantic compatibility despite regional AC base differences. Key participants included General Motors, Ford, Chrysler, BMW, Daimler, Audi, Porsche, and Volkswagen, who formed informal alliances to counter CHAdeMO's lead in deployed infrastructure and prioritize ISO-compliant communication for vehicle-to-charger handshakes.[12][13][14] By mid-2012, prototypes demonstrated feasibility, with the SAE approving the J1772 Combo specification on October 16, formalizing CCS 1.0 parameters including up to 200 A DC at 400-600 V. This milestone enabled initial vehicle integrations, such as GM's planned use in the 2014 Cadillac ELR, though commercial deployment lagged due to immature supply chains. The standard's design reflected causal priorities: empirical testing for thermal management and arcing prevention, rather than unproven high-power ambitions, positioning CCS for scalable infrastructure over niche alternatives.[15][16]Early Adoption and Expansion (2013–2019)
In the United States, early adoption of the CCS1 variant began in 2013 with joint testing of DC fast-charging stations by General Motors and BMW, marking a key step toward commercial deployment for North American vehicles.[17] In January of that year, Volkswagen and Eaton demonstrated a prototype CCS station, supported by commitments from eight automakers including Audi, BMW, Chrysler, Daimler, Ford, General Motors, and Volkswagen itself.[18] The first public CCS1 station opened in October 2013, followed by the Chevrolet Spark EV as the initial production vehicle offering CCS fast-charging capability by December.[19][20] In Europe, CCS2 implementation accelerated concurrently, with Volkswagen constructing the first public CCS quick-charge station—delivering 50 kW DC—in Wolfsburg in June 2013 to support testing of the VW e-Up, an early model equipped for the standard.[21] ABB introduced multistandard CCS chargers to the market in the second quarter of 2013, enabling both AC and DC compatibility for vehicles from multiple manufacturers.[21] By 2014, models such as the BMW i3 adopted CCS2 in Europe, contributing to faster infrastructure rollout compared to the U.S., where CHAdeMO stations initially outnumbered CCS ones.[22] Expansion gained momentum from 2015 onward through collaborative efforts. In the U.S., BMW, Volkswagen, and ChargePoint announced plans to install approximately 100 DC fast chargers supporting CCS by late 2015.[23] In Europe, a 2016 joint venture among BMW, Daimler, Ford, and the Volkswagen Group (including Audi and Porsche) aimed to deploy ultra-fast high-power CCS stations along major highways, targeting up to 400 sites by 2020.[24] This culminated in the November 2017 launch of the IONITY network, a pan-European high-power charging initiative using CCS2 to bolster long-distance EV travel.[25] By 2019, CCS compatibility extended to a growing roster of vehicles from BMW, General Motors, Volkswagen Group brands, and others, though infrastructure lagged behind vehicle adoption in some regions, with CHAdeMO retaining a station lead in the U.S.[19]Post-2020 Developments and Shifts
In Europe, the European Union's Alternative Fuels Infrastructure Regulation (AFIR), finalized in 2023 and entering force progressively from 2024, mandated CCS2 compatibility for DC fast charging on all new battery electric passenger cars, light commercial vehicles, and public fast chargers exceeding 50 kW starting in 2025, aiming to standardize infrastructure along major transport corridors with stations every 60 km by end-2025.[26] This built on prior voluntary adoption, enforcing CCS2 as the dominant standard amid growing EV sales, which reached over 2.4 million units in the EU in 2023, while phasing out alternatives like CHAdeMO through non-interoperable exemptions.[27] In North America, CCS1 faced competitive pressure from Tesla's North American Charging Standard (NACS), with Ford, General Motors, Rivian, and others announcing adoption of NACS ports for new models starting in 2025, following Tesla's opening of its Supercharger network to non-Tesla vehicles via CCS1 adapters in 2022–2023; this shift, accelerated by SAE J3400 standardization of NACS in 2023, prompted the Charging Interface Initiative (CharIN) to issue adapter best practices in April 2025 to maintain CCS interoperability amid declining CCS1 exclusivity in federally funded NEVI corridors.[28][29] By mid-2025, over a dozen automakers committed to NACS integration, reducing CCS1's projected market share for new EVs from near-universal in 2022 to under 50% by 2027, though adapters and dual-port vehicles mitigated fragmentation.[9] Technical advancements emphasized scalability, with CharIN's Megawatt Charging System (MCS)—an CCS-derived protocol for heavy-duty vehicles—advancing to 3.75 MW capabilities through prototype validations starting 2022, including ISO 15118-compliant Plug & Charge for automated sessions and initial bidirectional vehicle-to-grid (V2G) trials enabling up to Level 3 V2H/H by 2025.[30] Power delivery evolved to support 500–920 kW peaks in production systems, as demonstrated by commercial 720 kW CCS chargers deployed in Europe by 2023, enhancing charge times for 800 V architectures in vehicles like the Porsche Taycan and Hyundai Ioniq 5.[31] These updates, tested via CharIN's conformance programs, prioritized reliability over proprietary extensions, though NACS's simpler design drew criticism from CCS advocates for potentially limiting DC pin configurations in ultra-high-power scenarios.[32]Technical Design
Connector Variants (CCS1 and CCS2)
The Combined Charging System (CCS) employs two distinct connector variants, CCS1 and CCS2, to accommodate regional differences in electrical infrastructure and standards. CCS1, also designated as SAE Combo 1, integrates with the SAE J1772 Type 1 connector for alternating current (AC) charging and incorporates two additional pins for direct current (DC) fast charging, primarily serving North American markets.[33][12] In contrast, CCS2, or Combo 2, builds upon the IEC 62196 Type 2 connector, adding two DC pins to support both single- and three-phase AC alongside DC, and is the prevailing standard in Europe, Asia-Pacific regions, and other areas outside North America.[34][35] CCS1 features a five-pin J1772 base configuration—comprising two power pins (L1 and L2/neutral), ground, control pilot, and proximity detection—extended by DC positive and negative pins, resulting in seven total contacts. This design supports single-phase AC charging up to approximately 7.4 kW at 240 V and enables DC fast charging capabilities up to 350 kW under updated standards, though practical implementations often limit to 150-350 kW depending on vehicle and infrastructure.[36] The connector's rectangular form factor aligns with North American single-phase grids, with a maximum current rating for AC around 32 A.[37] CCS2 utilizes a seven-pin Type 2 base—including three AC phases (L1, L2, L3), neutral, ground, pilot, and proximity—augmented by two DC pins for a total of nine contacts, facilitating three-phase AC charging up to 43 kW at 400 V three-phase. DC fast charging mirrors CCS1's potential up to 350 kW, with liquid-cooled variants supporting higher sustained rates in advanced systems. This variant's compatibility with three-phase power reflects European grid norms, allowing higher AC throughput for residential and public Level 2 charging.[36][35][36]| Feature | CCS1 (Combo 1) | CCS2 (Combo 2) |
|---|---|---|
| Primary Region | North America | Europe and global (excl. NA) |
| Base AC Connector | SAE J1772 (Type 1) | IEC 62196 Type 2 |
| AC Phases Supported | Single-phase | Single- and three-phase |
| Max AC Power | ~7.4 kW (240 V, 32 A) | ~43 kW (400 V three-phase) |
| Total Pins/Contacts | 7 (5 AC + 2 DC) | 9 (7 AC + 2 DC) |
| Max DC Power | Up to 350 kW | Up to 350 kW |
| Standard References | SAE J1772 with Combo extension | IEC 62196-3 |