E-mobility: Port Wanted

Author: Joachim Geiger

Mar 24, 2021

At first glance, charging cables and plugs aren’t the central parameters for electric charging at wallboxes and charging stations. However, the right connection between vehicle and charging source is essential at both ends of the line for the current to flow into the battery. An overview of charging modes, cables, and plugs.

Few people would think of running a vacuum cleaner or electric kettle for eight hours straight under full load from a household socket with 230 volts. However, this is exactly what happens when the electric car is plugged in overnight in Charging Mode 2, using the charging cable provided by the manufacturer. How does this charging marathon not overwhelm the electrical installation in the home? “Mode 2 charging cables always have an in-cable control box (ICCB) between the vehicle plug and the connector plug, which performs basic control and protective functions,” explains Michael Ringleb, Electrical Engineering Product Manager (ELT) at DEKRA. For the expert, charging an electric car from the home socket is only the second-best option. After all, there’s an infrastructure in place for these vehicles, offering a high level of electrical safety and protection from overloading the installation.
Charging Mode 3 describes the use of the charging system with single-phase or three-phase charging with alternating current (AC). Typical applications are private wallboxes and charging stations in public areas. So do you just plug in and fill the battery with the charging source’s maximum power? That wouldn’t work because the car does have a say here. An onboard charger, which converts the alternating current into direct current (DC) on its way to the battery, determines how much energy is available to the battery per unit of time. Typical charging powers of onboard chargers are 3.7 kW, 7.4 kW, 11 kW and 22 kW. However, chargers don’t necessarily use three phases. True, there’s a trend in this direction in this country. However, the majority of electric cars are out and about with one-phase chargers. For an electric car enthusiast, it’s a matter of efficiency to connect vehicle and charging source with the appropriate cable. For this purpose, the aftermarket offers a wide range of single-phase and three-phase Mode 3 cables, which, with the appropriate cable cross-section and rated current – 16 or 32 amperes – make the desired charging performance possible.
Faulty refueling is impossible at the electric charging station
Choosing either the wrong cable or charger wouldn’t have serious consequences in this case. The charger with a charging power of 3.7 kW also works with the three-phase 22 kW cable. Conversely, the better-equipped onboard charger with three phases can also be charged with a single-phase charging cable. In both cases, the electric current only flows via one phase. Renault has recently come up with a special treat – the French have patented a charging system that automatically adapts to different AC charging powers of up to 22 kW. Volkswagen, on the other hand, is now equipping some models with a two-phase charger to achieve a charging power of 7.4 kW. However, a two-phase cable isn’t available on the market, not even for its weight in gold. If you want to make the best possible use of charging power, you need a three-phase cable with a charging power of 11 kW.
E-Mobility: One strong type dominates AC charging infrastructure in Europe
The use of hardware at the ends of a charging cable, however, is clear. “According to the charging station regulation (LSV), public charging stations for AC charging require the use of a Type 2 plug connection in accordance with EN 62196,” knows DEKRA expert Michael Ringleb. The infrastructure for AC charging is therefore primarily geared towards Type 2. Charging stations and wallboxes always have Type 2 couplings, while vehicles on the road are equipped with Type 2 sockets. The proper charging cable follows the pattern “Type-2-on-Type-2”. However, some Japanese and French vehicle manufacturers still have models on offer that are equipped with Type 1 sockets. For such cases, there are charging cables with a Type 2 plug for connection to the charging source and a Type 1 plug for the car.
DC charging stations move charging speeds into high gear
Charging Mode 4 can be described as the turbo variant of electric charging with direct current (DC). Filling up for a range of 100 kilometers in just a few minutes is no problem at DC charging stations. One of the reasons why the system really pushes the pace during charging is that it supplies the electric car directly with the direct current. A rectifier installed in the charging station eliminates the need for a detour via the onboard charger in the vehicle. The power spectrum for fast charging ranges from 50 kW for simpler systems to 350 kW for high-performance charging stations. In each case, the battery management system of the electric car decides at what power level the direct current ultimately flows into the battery. Incidentally, the charging cable is permanently installed in fast charging stations.
The CCS connects the worlds of AC and DC
Here, too, the question of the right plug for the charging cable has already been answered. An EU directive established the Combined Charging System (CCS) as the standard for plugs and couplers for electric cars back in October 2014. The CCS combines the worlds of AC and DC charging. “The combo plug combines a Type 2 plug with two additional power contacts for DC charging in one plug housing,” explains DEKRA expert Ringleb. An electric car with the Combo 2 charging socket can therefore tap direct current at the charging station’s fast charger, and alternating current at the AC charging station via three phases. All that is needed is a normal Type 2 AC charging cable that can be plugged into the upper chamber of the Combo 2 socket.
Tesla Superchargers could soon be available to all users
The so-called CHAdeMO plug can also be found at many fast-charging stations. Some Asian manufacturers, and in some cases also Citroen and Peugeot, use this system developed in Japan, which allows charging processes of up to 100 kW. And Tesla’s high-performance charging stations are likely to become a permanent fixture at electric charging stations. The latest generation of these Superchargers for the European market is equipped with a CCS plug. This means that – at least in theory – this charging infrastructure could be used for vehicles from other manufacturers. According to recent reports, Tesla CEO Elon Musk is already toying with the idea of opening up the Superchargers to new customer groups.