Fast Charge Standards

Research has shown that electric car use rose when the CHAdeMO fast charging network was built in Japan, but manufacturers can’t agree on a common standard for the charging interface.

Could this hinder the rollout in the UK?

The effectiveness of electric vehicles in reducing emissions can only really be evaluated once a realistic charging infrastructure is in place. When readily available, fast charging will undoubtedly make EV choice a lot more attractive and go some way to address concerns of range anxiety. Thirty minutes for an eighty per cent charge is much more realistic.

This chicken and egg scenario is being figured out, albeit gradually, as advanced charging equipment is making its way into the picture. It’s a valuable market - Pike Research said last year that annual revenue generated by makers of EV charging equipment will increase more than tenfold between 2011 and 2017 to around $4.3 billion.

For faster charging, dedicated chargers can be built in permanent locations and provided with high-amperage connections to the grid. But uncertainty over a common standard for the connections is a potential future hurdle, and the real power rests with the car manufacturers. There are two competing standards - CHAdeMO and SAE DC Fast Charge.

CHAdeMO is leading the way. It was developed several years ago by Tokyo Electric Power Company (TEPCO) and a consortium of Japanese automakers including Nissan, Mitsubishi, Toyota and Suburu. CHAdeMO has been in use since 2008 as the trade name of a quick charging method for battery electric vehicles delivering up to 62.5 kW of high-voltage direct current via a special electrical connector. As well as the Nissan LEAF, the Mitsubishi IMiEV, Renault eKANGOO, Peugeot iON and Citroen C-ZERO are all available EVs that are compatible with CHAdeMO.

At the time of writing, there are barely 1500 CHAdeMO charging points installed worldwide, and the bulk of these are in Japan (1236) with only 40 in the UK, mainly at Nissan dealerships. This is set to change, and installations are being announced regularly. Research has shown that when the CHAdeMO network was built in Japan, electric car use went up dramatically, suggesting that the existence of a fast charging network alleviates range anxiety.

Competing standard
However, manufacturers in the US and Germany are leaning towards adopting a quick-charge connector standard based on the SAE J1772 AC/DC combo connector. 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 users to charge at most existing charging stations regardless of power source. This charge format provides for a single, multi-function interface built into the vehicle, rather than two separate plugs, which can potentially deliver high-power charging of up to 100kW in future. The SAE DC fast charging consortium includes Audi, BMW, Daimler, Ford, General Motors, Porsche and Volkswagen.

The debate continued in Los Angeles this year as the city hosted 26th International Electric Vehicle Symposium in May, where BMW, Ford, General Motors and Volkswagen all demonstrated the single-port system. The SAE consortium argues that car makers are used to to designing a single hole for the fuel, but the Nissan Leaf designers managed to squeeze both standard and CHAdeMO plugs into one large hole in the nose of the car.

The new standard is expected to be finalised later this year, but it is unknown how long it will take for the new charging port to begin to appear in electric cars that we can actually buy. It’s a potentially tricky situation for organisations both private and public to invest in a fast charging infrastructure given the uncertainty surrounding this standard, but some charging point manufacturers, such as Schneider Electric, have already announced CHAdeMO compliant stations that can be upgraded to the SAE standard once its finished.

Adapters
Would it be possible to build an adapter for the car? The CHAdeMO plug has two large pins for a DC connection, and several smaller pins for a CAN-bus connection allowing the car and the charger to talk with each other. The new SAE plug has two pins for the DC connection, and uses the HomePlug Green Phy communication protocol to communicate between car and charging station. If an adapter could be built, it would be complex.

In time, this may well pan out in a similar way to the VHS/Betamax video player scenario in the eighties - most experts considered the Betamax to be a far superior format, yet VHS made its way through to dominate. Eventually, the car manufacturers, and ultimately the buyers, will decide.

Wahid Nawabi of US-based charging solutions provider Aerovironment put it into perspective. He told autobloggreen: “People are making a big deal about a standard that there is not a lot of market for, yet. I believe that one uniform standard that everyone can agree to is very positive for the industry. Whether that ends up being CHAdeMO or combo or something different, to me it’s semantics. Today, the standard that makes the most sense for the consumer is CHAdeMO because that’s out there and that’s what the cars are shipping with. So, should that be the one? I think that makes a lot of sense. You can argue that one is better, I’m sure. But it’s what’s better for you, an apple or an orange? If you’re hungry, you need food.”

Further information
CHAdeMO Association - www.chademo.com
SAE International - www.sae.org
Facilitating e-mobility: EURELECTRIC views on charging infrastructure - tinyurl.com/c5zhoao