Rapid charging: Mission "15 minutes"

EQC 400: combined power consumption: 21.3-20.2 kWh/100 km; combined CO₂ emissions: 0 g/km)**

Joint Venture IONITY is currently working on behalf of BMW, Daimler, Ford and VW to develop a Europe-wide high-speed charging network for electric vehicles. We test public charging with the EQC. In the process, we find out more about high power charging (HPC) and the driving habits of long-distance drivers.

With rapid charging, it's sometimes a matter of milliseconds. Irrespective of which electric vehicle docks at a charging point, it needs to speak the same language as its electricity supplier – for example in order to trigger the charging procedure at just the right moment. These milliseconds are vital to the success of IONITY. The company has set itself the objective of building the most reliable rapid charging network in Europe. At its test workshop in the northern suburbs of Munich, electrical engineers and IT specialists are therefore working hard to ensure that any misunderstandings in the communication between vehicle, charging station and software are pre-empted and systematically excluded.

It is meticulous work. "And from a technical point of view, it's incredibly exciting", adds Dr. Susanne Koblitz, the physicist at IONITY responsible for the Charging Technology unit. "As one of the very first companies to specialize in high-speed charging, we are a key player when it comes to developing a European standard." A standard that ensures that alternating current (AC) is converted outside the vehicle into direct current (DC) before being fed into the battery at a rate that is adjusted to the size and charge status of the vehicle battery.

Dr. Susanne Koblitz (center) with her colleagues in a team meeting at IONITY's head office in the northern suburbs of Munich.

A quick coffee while you charge

IONITY offers a charging performance of up to 350 kilowatts at its charging points. Even just a few years ago, 50 kilowatts was considered fast. What is the benefit of so-called "high power charging"? "Our aim is to get to a point where, over a long distance, the charging times coincide with the natural pattern of the driver's breaks", explains Dr. Susanne Koblitz. Surveys show: most people will take a short break every three to four hours. And many of them will use this time for a snack at a service area, investing 15 to 20 minutes to do so. If we extrapolate these findings over the distance covered, we find that the consumption to be recharged at each stop amounts to around 80 to 100 kilowatts. The 350 kilowatts provided by IONITY thus offer the wherewithal to reduce the charging time to the duration of a 15-minute coffee break.

The automobile industry confirms this requirement for shorter DC charging times: the European manufacturers have already announced ten new rapid-charging models with correspondingly powerful batteries for 2020 – the fastest of which has a capacity of 270 kilowatts. In other words, no electric vehicle is currently able to exhaust the potential provided by IONITY. This will inevitably change over the next five years. The EQC, with its maximum DC charging capacity of 110 kilowatts, currently needs around 40 minutes to recharge its battery from almost empty.

IONITY's "high power charging" points deliver a charging capacity of 350 kW.

"Plug and Charge" instead of yet another card

Along with time savings and reliability, IONITY has made the simple operation of its charging points one of its main tenets. "Ideally, the process should be as simple as the sort of filling up that we're already used to: arrive, plug in, charge, drive on", says company spokesman Paul Entwistle as we drive in the EQC from the test workshop to the next IONITY high-speed charging point in the south of Munich. In order to implement this so-called "Plug and Charge" concept, the startup first needed to establish a uniform, Europe-wide payment system. Drivers of electric vehicles have three options here: they can use the customer card of their mobility provider, the IONITY app on their smartphone, or the QR code on the charging station itself. Looking ahead, it is even possible to imagine that the info screens on the charging stations could disappear. The more intuitive, the better – and the more convenient.

The newest, 2.60-meter-tall IONITY charging stations are furnished for this very reason with light signals that indicate to drivers even from a considerable distance where the next available charging point is to be found.

Leading the way with conviction

We find out more about IONITY as we go along. This niche provider was founded in 2017 as a joint venture between the four automobile manufacturers BMW, Daimler, Ford and VW, with the objective of smoothing the path to electric mobility. In under two years, the new company has managed to create from scratch an infrastructure for public high-speed charging along Europe's major transit routes. By December 2019 there were some 2000 charging parks with up to six charging points each. The aim is to have twice as many as this across Europe within twelve months from now.

The first visible signs of success are the result of what has, at times, been some very tedious preliminary work. "Our objective, right from the start, was to include 24 countries. So we began by making contact with the local authorities, to get all the authorizations we needed", says Paul Entwistle. "Some of the people we spoke to had never heard of high-speed charging, so our engineers really had their work cut out to convince them."

In addition, IONITY is dependent in each country on finding energy partners who can supply the company with power generated from renewable sources. The charging station operator hopes to provide electricity that is virtually 100 percent "green" right across Europe, in order to come as close as possible to the vision of emission-free driving. Ultimately, and importantly, IONITY is also dependent upon its cooperation agreements with the operators of service areas, whose infrastructure the newcomer relies on for its charging parks. "It has only been possible to pull this all together in such a short time because we have a team where everyone gives their all in terms both of expertise and commitment", underlines Paul Entwistle. We have people of twelve nationalities working at IONITY, with all sorts of different skill sets. Most of them come from the automotive or energy sectors, although we also have marketing and communication experts. "What unites us is the will to think outside the box and to help shape the ongoing transformation of our respective industries." Four heralds of this transformation welcome us with their illuminated green signals at the autobahn service area Holzkirchen South. Ready for real-life testing

Real-life testing: this is how high-speed charging with the EQC works

Alternating current requires communication

We use the charging time to chat about the challenges of charging using direct current: the clear time saving achievable by comparison with the use of alternating current to charge from a household power socket is somewhat offset by the greater susceptibility of the technology to faults. "Many drivers of electric vehicles allow a certain extra range as a buffer so that, if needs be, they can drive on to another charging station that is actually working", says Dr. Susanne Koblitz. "I've been driving an electric car myself now for nine months and can say, with absolute conviction, that I have never needed this reserve at our charging stations."

Dr. Susanne Koblitz is herself an enthusiastic electric-car driver.

The physicist is nevertheless well aware of the teething problems faced with this 'young' technology: these stem from the physical necessity of converting the alternating current from the network into direct current that is compatible with the battery. This process requires a transformer, the size of which is in direct proportion to the charging capacity. In the case of high-speed charging, it begins to take on dimensions such as to make it more sensible to accommodate it outside the vehicle. The conversion therefore no longer takes place in the car, but directly at the charging point.

"The fundamental challenge that we have with this external conversion process is that the charging station must generate precisely the voltage that the battery is able to take on board. However, this changes constantly according to the charge level of the battery." Dr. Koblitz uses the image of a concert hall filling up to illustrate these fluctuations: the first audience members have to get their bearings first of all in the empty space and therefore need a little longer to find their seats. Once a few seats are taken, people find it easier to orientate themselves. The last 20 percent, on the other hand, once again need longer, because they first have to work their way through to their seats.

With charging, it is the lithium ions that have to find their way through the layers of molecules in the battery cell to their rightful place. If the battery is already quite full, it takes them longer to do this. The battery then calls upon the charging station to reduce the flow of electricity. "This involves a constant process of communication between the vehicle and the charging station. Here at IONITY we have made significant progress in this respect over the last couple of years", Susanne Koblitz summarizes.

The app on our smartphone shows that the charging process is complete. It has taken 33 minutes to charge from 22 to 80 percent. Half an hour, during which the topic of conversation kept coming back to the future of driving. "As a driver myself I do of course wonder what will be coming our way in the next ten, twenty years", reflects Dr. Susanne Koblitz. "When I say this, I'm not thinking so much about the drivetrain or the battery - the manufacturers are already working wonders in that respect. Much more exciting is the question as to what requirements the automobile of the future will need to meet. And how these requirements can be satisfied, over the long term. I'd like to think we could also become a little more visionary about things like this, here in Germany."

We use cookies

We want to make our website more user-friendly and continuously improve it. If you continue to use the website, you agree to the use of cookies.