Electric Cars: Infrastructure for 400+ kW charging power is being created

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Electromobility itself is old, but for many drivers, its widespread adoption is still new. For several years, the leading edge of charging infrastructure, in terms of its performance, was technically ahead of its users: who, two years ago, could charge at more than 300 kW? Last year, the number of models capable of this grew noticeably. Now, operators of charging points and manufacturers of charging stations are being called upon. Both are currently in the process of building charging capabilities with 400 kW. And it won't stop there.

CCS2 Specification

Until now, the situation was clear: most charging stations are connected with 500 Amperes. Depending on the car's voltage level, 400 or 800 Volts are currently common, resulting in a maximum charging power of 200 or 400 kW. The CCS2 specification allows for a maximum of 500 A and 1000 Volts, which theoretically would result in a maximum charging power of 500 kW. However, no car manufacturer has dared to go above 900 Volts so far.

After a few years when 300 kW was enough to fully utilize even the fastest charging electric cars, cars like the Volvo EX60, Smart #5 (Test), or BMW iX3 are now coming onto the market that can accept more than 300 kW. For these models, 400-kW charging stations are usually barely sufficient. Xpeng promises up to 525 kW for the current top-of-the-line version of the G9, which is even more than the CCS2 specification actually allows. However, if you want to fully utilize this, you'll currently find yourself out of luck almost everywhere in Europe.

On the other hand, it must be stated: even with 400 kW charging power, theoretically 100 kWh could be recharged in 15 minutes. Even though long-lasting charging infrastructure should always have a head start: in the short term, electric cars will not be able to absorb such an amount of energy in such a short time. An example calculation for illustration: The Volvo EX60 offers a traction battery with 112 kWh net in its top model P12. Volvo promises to be able to recharge the 70 percent between 10 and 80 percent charge level, which corresponds to 78.4 kWh, in 19 minutes. The peak charging power is 370 kW, and the average net charging power between 10 and 80 percent is almost 248 kW.

If the development of recent years continues, both the peak and average charging power in many electric cars will increase significantly. Because the times when customers were impressed by short-lived power peaks are long gone. What counts is how quickly a real range can be replenished. That's why the indication of how many kilometers can be recharged in ten minutes is becoming increasingly widespread. It should be noted that this value applies to the combined WLTP consumption and ideal charging conditions.

Network of 400-kW Charging Points is Emerging

The hardware providers for charging infrastructure must therefore upgrade, and of course, they have been doing so for a long time. One challenge in this is minimizing charging losses in the station. For example, when up to 260 kW were drawn in the test of the Hyundai Ioniq 5, the cooling of the station was clearly audible. For this reason, Alpitronic also relies on silicon carbide modules, which, according to the manufacturer's promise, halve the power loss and achieve an efficiency of 97.5 percent. The maximum charging current per HYC400 station is twice 600 A. Anyone who wants to set up a charging park with a whole row of such stations therefore needs a very solid connection to the medium-voltage grid and also powerful hardware in front of the station. The leading DC charging network provider in Germany, EnBW, like its competitors Fastned and EWEGo, has already put some charging points with 400 kW into operation.

This also applies to the provider Ionity, which is already planning with charging power of up to 600 kW. In principle, it's positive to see how charging is developing, says Linda Boll, Country Director of Fastned Germany. "There are no 600-kW charging stations with a CCS connection in Germany yet. That's already entering the high-voltage range, meaning megawatt charging like for trucks." Alpitronic offers the HYC1000 for this purpose, with a charging power of up to one megawatt.

Dynamic Power Distribution

This station becomes particularly interesting for operators in combination with a central "Power Cabinet" that can variably distribute the charging power to each connected point. This allows up to eight electric vehicles to be charged simultaneously with dynamic power distribution to the individual charging points, or a single vehicle to be charged with up to 600 kW. For this, the specifications of the CCS2 connections would have to be changed. There might be less time for this than it currently seems. Nio has announced a charging power of 600 kW for the luxury model ET9, which is not yet offered in Germany. A portion of the energy content of 120 kWh, which its traction battery offers, should therefore be rapidly replenished, provided the infrastructure can keep up.

(mfz)