TECH ED’S CHOICE
EV CHARGING STANDARDS
On reading CAR’S article on the Jaguar I-pace (August 2018), I wondered if an agreement has been reached among manufacturers on standardisation of charging stations? It would be annoying, to put it mildly, if you got to, say, Colesberg, and found a plug doesn’t fit. DOUG SCOTT Rhenosterspruit The current answer is “no” but hopefully the standards will eventually merge into one.
Background on battery charging
Remember, batteries are direct current (DC) while the electrical grid employs alternating current (AC). Therefore, to charge an electric vehicle using a wall socket at home, the AC current needs to be converted to DC by an onboard charger before the battery can be charged. The maximum power from the wall socket is limited to 3,3 kw (a 15 A socket at 220 V), so the charger can be small enough to fit in the vehicle for normal (slow) charging.
For fast charging (50 kw and higher), the charger cannot be housed in the car and is proprietary, i.e. a charging station. When an EV plugs into a fast charger, the charger has already converted the AC supply to DC and supplies the EV battery directly with DC.
It’s clear the charging methods (slow and fast) need two separate connecters (and plugs).
For standard (slow) charging, many manufacturers opted for the Type 1 connector because it offered safe home charging with an onboard charger. Because three-phase power supply is quite common in Germany, the German OEMS decided to take the Type 1 connector and add two extra pins to allow three-phase home charging that ups the charging rate considerably. This connector is now known as the Type 2 connector and is the most common connector for standard charging.
When it comes to fast charging, there are again more options. Japanese manufacturers agreed on the Charge on the Move (CHADEMO) standard initially fixed at 50 kw with a communication protocol over the CAN bus. Manufacturers that signed up to this standard include Mitsubishi, Nissan, Toyota and it was licensed to Kia and PSA.
Germany was, however, not prepared to pay the licensing fee for a technology it did not agree with and adapted the Type 2 connector with two extra connectors for DC positive and negative and called this new connector the Combined Charging System (CCS), as it allows normal and fast charging through the same connector.
Tesla also uses the Type 2 connector but handles fast charging (up to 120 kw) differently when plugged into its own Supercharger charging network.
One charger for all
At least companies such as ABB are developing charging stations with connectors for all the above, almost like a fuel station with different fuels (93, 95 and diesel, for example). Let’s hope an agreement is soon reached between manufacturers to standardise the charging system.