Two industry groups, Japan’s CHAdeMO and the China Electricity Council, which are the world’s strongest proponents of electric vehicles (EVs), announced in late August they would codevelop an ultrafast charging protocol for EVs. Now, the partners, under the supervision of both the Japanese and Chinese governments, are inviting other countries to join the endeavor. Their goal is to develop a global standard for all types of EVs by 2020.
CHAdeMO, a consortium of automotive, power generation, and IT companies (including Kia, Mitsubishi Motors, and Nissan), has the largest global installation of DC chargers for electric vehicles: 22,647 units operating in 71 countries as of September, according to the group’s own figures. This includes more than 2,900 in North America, and over 7,900 in Europe.
CHAdeMO’s Chinese counterpart, China Electricity Council (CEC), counts 270,000 chargers using its GB/T standard installed in China and India. Together, the two groups account for more than 90 percent of the installed EV fast charger market—that is, DC charging stations up to 120 kilowatts that connect directly to the battery.
Both organizations presently use their own charging standards, which share some common features such as the controller area network (or CAN bus), which is a standard for communications between electronic control units for features such as airbags, audio system, and the engine control system.
The new EV charger standard goes by the working name of ChaoJi. Makoto Yoshida, Secretary General of the CHAdeMO Association and general manager at Nissan, in a recent briefing for the foreign press in Tokyo, noted that “nothing is finalized” in the specifications drawn for it to date, and there is room for input from countries that join the endeavor.
Maximum power for the new standard is tentatively set at 900 kW (1,500 x 600 amperes) to meet the needs of high-powered batteries of the future. This will be capable of charging large vehicles such as earth-moving equipment, buses, trucks, and helicopters at faster speeds. For example, whereas a 50-kW charger takes about 30 minutes to charge a 25 kilowatt-hour battery today, a 900-kW charger of the future could charge a 450-kWh battery in 30 minutes.
Before that happens, however, CHAdeMO intends to modify its specification for upcoming chargers to handle 350 kW and 500 kW-plus in the new ChaoJi standard. It will also require manufacturers to include a new connector design and liquid cooling cables.
One area the ChaoJi standard will not compromise on is communication within vehicles and between vehicles and chargers. Both the current CHAdeMO and GB/T standards use the CAN bus, and this will be the partners’ choice going forward. One of CAN’s advantages is that it allows communications between a vehicles’ control units without the need for dedicated wiring between them and without overloading the controller computer.
“When it comes to communication between a vehicle and the charger, the sequence of the communication as well as the content of that communication should remain the same,” Yoshida explains. “The same rules should be applied to high-power charging [all the way] down to low-power charging.”
Another area where the partners are not willing to compromise is in making the new protocol backward compatible with the present CHAdeMO and GB/T standards. This would allow current chargers to continue to be used under the new standard.
Yoshida added that they are also thinking of developing a standard that covers the low end of the market for vehicles such as scooters, forklifts, and lightweight cars. Such a charger would be rated at between 2 to 20 kW.
Despite the current dominance of the CHAdeMO and GB/T standards, a third standard developed by the Society of Automotive Engineers could pose a long-term threat. Named Combined Charging System (CCS), it is backed by BMW, Ford, General Motors, VW, and others. It comes in two flavors that combine AC and DC charging in a single connector and are dubbed Combo 1 and Combo 2. Combo 1 uses a single-phase connector for AC and is used in North America. Combo 2 is found elsewhere and employs both single-phase and three-phase connections for AC. Although CCS came late to the charger party in 2014 (five years after CHAdeMO's debut) its take-up is reportedly growing fast.
A fourth proprietary standard, devised by Tesla, is also gaining ground. The Tesla Supercharger system provides three charging speeds: trickle (120 volts/15–20 A), medium (240 V/80 A), and fast (480 V/300 A) providing driving ranges from 3 to 273 kilometers per hour of charging.
The confusion caused by incompatible charger standards is only one of the obstacles preventing a faster adoption of EVs. Other hurdles include high price, limited charging infrastructure, driving range anxiety, and slow charging time.
Should CHAdeMO and CEC gain the support of third countries to create an industry-wide standard for ultrafast charging, it could eliminate some of these hurdles.
But the introduction of a third standard in addition to the existing CHAdeMO and CCS standards will likely pose a major headache for hardware developers, says Kouhei Sagawa, an assistant professor in electrical engineering at Tokai University, in Tokyo. “This will lead to an increase in the development period and in the cost,” he says.
Sagawa, who entered academia after working on the development of electric vehicles for Subaru, points out that auto manufacturers need to change the electrical design of their cars for each new standard, swap out hardware mountings, and test electromagnetic compatibility, among other tasks.
To reduce the burden for manufacturers and enable a smooth deployment of the new charging infrastructure, Sagawa says the new standard should maintain a close affinity with the existing standards. In addition, the EV industry should develop new technologies such as semi-automatic and automatic methods of connecting vehicles to chargers. And since higher currents will be used, they must also reconsider cable sizes.
Meanwhile, CHAdeMO and CEC are pushing ahead with their efforts. Yoshida says the two organizations have approached several countries about joining them, including Australia, Chile, Germany, India, South Korea, and the ASEAN countries.
He added that, provided there is agreement on backward compatibility with existing CHAdeMO standards in the United States and Europe, and the CAN bus remains in place, “We welcome countries who are interested to participate in developing the standard.”
Just how many countries take up that invitation will likely determine whether the new effort creates a truly global standard or merely adds to the present confusion.