JFE Engineering Corp disclosed the concept of the "super-rapid charging system," which is being developed by the company, June 16, 2010, at Smart Grid Exhibition 2010 in Tokyo.

The system can charge the battery of a normal electric passenger vehicle to 50% capacity in three minutes and to 70% capacity in five minutes, which are much faster than the charging speeds of the existing charging systems for electric vehicles (EVs). Therefore, the new system is expected to enhance the convenience of EVs.

JFE Engineering will conduct a field test of the new charging system in fiscal 2010. And it is planning to commercialize the system when EVs supporting the rapid charging are released in the future.

Rapid charging systems that have already been commercialized by some companies (up to 500V x 125A) are based on the "CHAdeMO," a Japanese standard for EV rapid chargers, and are capable of charging an EV to about 80% capacity in 30 minutes.

However, because the new system proposed by JFE Engineering uses 500-600A of current, which is about five times higher than the current of the existing systems, it is not compatible with the CHAdeMO. Therefore, the new system cannot be used with Mitsubishi Motors Corp's "i-MiEV," Nissan Motor Co Ltd's "Leaf" and other electric vehicles that support the CHAdeMO.

Moreover, to commercialize the new system, it is necessary for the batteries of EVs to withstand the rapid charging (50% capacity in three minutes). JFE Engineering is currently promoting the adoption of batteries supporting the super-rapid charging to automakers so that their next-generation EVs will support the new system.

Another feature of the super-rapid charging system is that it can be used with a low voltage power supply (20kW, AC200V). The existing rapid charging systems require a higher power supply voltage (50kW or more, AC6.6kV).

The super-rapid charger for the new system has two batteries inside. One is a high-capacity battery used to store grid electricity during nighttime hours. And the other is a high-output battery that rapidly charges an EV by using the electricity stored in the high-capacity battery. But JFE Engineering did not reveal other details of the system.