The prototype of a charging station with an output of up to 450 kW was inaugurated in Jettingen-Scheppach, Bavaria, on December 12, 2018. Electric research vehicles created in the 'FastCharge' project demonstrate charging times of less than three minutes for the first 100 km range and 15 minutes for a full charge (10 to 80% state of charge) at this ultra-fast charging station. The new charging station is suitable for electric models of all brands with the Type 2 version of the Combined Charging System (CCS), which is commonly used in Europe, and can be used free of charge with immediate effect.

Details about the FastCharge

The 'FastCharge' research project, which was launched in July 2016, is being run by an industrial consortium led by BMW and including Allego, Phoenix ContactE-Mobility, Porsche and Siemens. The project is being funded by the Federal Ministry of Transport and Digital Infrastructure with a total of 7.8 million euros. The implementation of the funding guidelines is being coordinated by the National Organization Hydrogen and Fuel Cell Technology (NOW).

As part of 'FastCharge', the companies are investigating which technical requirements must be met by vehicles andinfrastructure in order to be able to use the high charging capacities.

The basis for this is a high-performance charging infrastructure. The Siemens energy supply system used in the project makes it possible to test the limits of the fast-charging capability of vehicle batteries. It can already work with higher voltages of up to 920 volts. Both the high-performance electronics for the charging connections and the communication interface to the electric vehicles have been integrated into the system. This charging controller automatically adjusts the power output so that different electric cars can be charged using one infrastructure. The flexible, modular architecture of the system also allows several vehicles to be charged simultaneously. Thanks to charging at high currents and voltages, it can be used for a wide range of different applications, such as fleet charging solutions or, as in this case, charging on freeways. For the connection to the public power grid in Jettingen-Scheppach, a charging container with two charging connections was realized in the project: One connection has an unprecedented maximum charging capacity of 450 kW, while the second delivers up to 175 kW .

Cool properly

The charging station prototypes now presented by Allego use the CCS charging plugs in the Type 2 version for Europe. Cooled high-power charging cables (HPC) from Phoenix Contact, which are fully CCS-compatible, are used to meet the requirements of fast, high-power charging. A water-glycol mixture is used as the cooling fluid, which allows the cooling circuit to be semi-open. In contrast to hermetically sealed systems that work with oil, this makes maintenance comparatively easy, for example when topping up the coolant.

One challenge was to avoid crushing the cooling hoses in the charging line when connecting them to the charging station, as would happen with a conventional cable gland. In this case, the cooling flow and therefore the cooling capacity would be impaired. Phoenix Contact has solved this problem with a specially developed wall bushing with defined interfaces for power transmission, communication and cooling as well as integrated strain relief.

Charging power of the station adapts

Depending on the vehicle model, the new ultra-fast charging station can be used for vehicles with both 400 V and 800 V battery systems. Its charging power automatically adapts to the maximum permissible charging power of the vehicle. The time savings that can be achieved through higher charging capacities can be illustrated using the example of the BMW i3 research vehicle. It takes 15 minutes to charge the high-voltage battery with a net capacity of 57 kWh from 10 to 80 % SOC. This can be achieved on the vehicle side thanks to the specially developed high-voltage storage system in combination with an intelligent charging strategy. This includes precise preconditioning of the storage temperature at the start of charging, temperature management during the charging process and a perfectly coordinated charging power profile over time. The charging process takes place via an innovative vehicle-side multi-voltage network with a high-voltage DC/DC converter, in which the required 800 V input voltage of the charging station is transformed to the lower 400 V system voltage of the i3 research vehicle. Thanks to the HV-DC/DC, the vehicle can also charge backwards-compatible at all old and future charging stations. Secure communication between the vehicle and the charging station is crucial for reliable operation. For this reason, standardization topics for interoperability are also being researched and brought to standardization committees.

The Porsche research vehicle with a net battery capacity of around 90 kWh achieves a charging capacity of over 400 kW and thus enables charging times of less than three minutes for the first 100 km range.