Joint China and Japan ChaoJi project works towards “CHAdeMO 3.0”

Good progress is being reported on the joint effort by the predominantly Japanese CHAdeMO Association and China’s State Grid utility operator on their new common connector plug design for future vehicles from both countries.

Last summer they announced an agreement to work together on a common connector design called ChaoJi for future use in Japan, China, and other regions of the world using the CHAdeMO or GB/T connector today. ChaoJi (超级) means “super” in Chinese.

CHAdeMO is the DC fast charging connector design used, for example, in the Nissan LEAF. Electric vehicles sold in China use a GB/T charging standard unique to China.

Details of the ChaoJi effort were initially sketchy but are now becoming more clear. The goal is to design a new common plug and vehicle inlet that can support up to 600A at up to 1,500V for a total power of 900 kW. This compares to the CHAdeMO 2.0 specification updated last year to support 400A at up to 1,000V or 400 kW. China’s GB/T DC charging standard has supported 250A at up to 750V for 188 kW.

Although the CHAdeMO 2.0 specification allows up to 400A there are no actual liquid-cooled cables and plugs commercially available so charging is, in practice, limited to 250A or about 94 kW today on the 62 kWh Nissan LEAF PLUS.

Future vehicles can use chargers with older CHAdeMO plugs or China’s GB/T plugs by way of an adapter that a driver can temporarily insert into the vehicle inlet.

Older vehicles using CHAdeMO 2.0 and earlier or China’s existing GB/T design, however, are not allowed to use an adapter and can only fast DC charge using the older type of plugs.

A Chinese variant of the newly designed plug called ChaoJi-1 and a Japanese variant called ChaoJi-2 although they are physically interoperable without an adapter. It’s not clear what the exact differences are or whether the two variants will be merged before the standard is finalized. The two variants could reflect optional “combo” bundlings of the new common DC ChaoJi plug with the existing AC charging plug standard used in each country analogous to the CCS Type 1 and Type 2 “combo” designs which combined both AC and DC charging together in a single plug.

The existing CHAdeMO and the GB/T standards communicate with the vehicle using CAN bus networking which is also widely used within vehicles to allow components of a car to communicate with each other. The new ChaoJi design continues to use CAN bus which eases backwards compatibility when using inlet adapters with older charger cables.

Like CHAdeMO, ChaoJi will continue to support the bidirectional flow of power so that the battery pack within a car can also be used to export power from the car back into the grid or into a home during a power outage.