Makers of plug-in hybrids and electric vehicles have already adopted a common connector standard for so-called Level 1and Level 2 charging, at 110/120 and 220/240 volts respectively.
But agreement on a common plug for Level 3, also called "fast" chargers, which operate at 440-to-600 volts, depending on region, has been elusive.
A lack of such standard has been blamed for slowing down the installation of commercial fast charge outlets, which can potentially recharge an EV in 15-20 minutes.
Japanese companies have been promoting one standard while their American and European counterparts have been leaning in another direction.
Several American and German automakers (Audi, BMW, Chrysler, Daimler, Ford, General Motors, Porsche and Volkswagen) took a major step towards resolving that standoff this week by announcing an agreement to support a harmonized single-port fast charging approach – called DC Fast Charging with a Combined Charging System – for use on electric vehicles in Europe and the United States.
The combined charging system integrates one-phase AC-charging, fast three-phase AC-charging, DC-charging at home and ultra-fast DC-charging at public stations into one vehicle inlet. This will allow customers to charge at most existing charging stations regardless of power source and may speed more affordable adoption of a standardized infrastructure, they say.
The International Society of Automotive Engineers (SAE) has chosen the Combined Charging System as the fast-charging methodology for a standard that incrementally extends the existing Type 1-based AC charging. The standard is to be officially published this summer.
ACEA, the European association of vehicle manufacturers has also selected the Combined Charging System as its AC/DC charging interface for all new vehicle types in Europe beginning in 2017.
The charging system design is said to be based on collaborative reviews and analysis of existing charging strategies, the ergonomics of the connector and preferences of U.S. and European customers.
The system was developed for all international vehicle markets and creates a uniform standard with identical electrical systems, charge controllers, package dimensions and safety mechanisms.
The system maximizes capability for integration with future smart grid developments through common broadband communication methods regardless of the global location of the charging system, its proponents say.
The combined charging approach is also expected to reduce development and infrastructure complexity, improve charging reliability, reduce the total cost-of-ownership for end customers and provide low maintenance costs.
Commercially available combined charging units are projected to be available later this year.
All committed OEMs have vehicles in development that will use the Combined Charging System. The first vehicles to use this system will reach the market in 2013.
Whether or not the Japanese automakers will capitulate and adopt this common standard or continue to go their own way remains to be seen.