HV-MELA-BAT – High-Voltage Megawatt Charging System for Heavy-Duty and Passenger Traffic

A new charging standard is being worked on for battery-powered heavy-duty and passenger transport; the Megawatt Charging System (MCS). This should enable a charging voltage of up to 1250 volts and currents of up to 3000 amperes. In the »HV-MELA-BAT« project, a charging system is to be developed that is based on the new MCS standard and at the same time is compatible with the already implemented CCS1 and CCS2 standards. In addition to the required power electronics, the system also includes stationary storage in the form of a lithium battery pack. With its help, the power drawn from the grid required for the charging system can be significantly reduced, which in turn can lower the operating costs of the charging system.

For the market segment of battery-powered heavy-duty and passenger transport, work is underway on future charging standards that provide for a continuous current carrying capacity of up to 3000 A at a charging voltage of 1250 V.

The requirements in this case regarding the transmission power, resulting from the load profiles to be realized for heavy goods and passenger traffic to electrified on international main traffic axes are several times higher compared to the ultra-fast car chargers. . The consortium sees the proposed project implementation as an opportunity to combine the highly innovative charging systems and their components in a functional prototype and thus address the field of battery-electric heavy-duty and passenger transport. Against the background of the characteristics of today's commercially available vehicle energy storage systems, the construction and demonstration of a technologically novel megawatt charging system (MCS - Megawatt Charging System) with a charging power of 1 MW at a working voltage of 1250 V represents a sensible intermediate step towards a future charging power above 3.5 MW.

The central components of the R&D project proposed here are the power electronic converters, such as the grid-side rectifier (500 kW - 1 MW) and a modular interconnection of DC/DC converters for galvanic isolation and for adapting the charging voltages in the vehicle (4 x 250 kW). Likewise, the system will be supplemented by a buffer storage of second-life batteries so that the grid connection power can be reduced. The system will be upgraded to address the widest possible range of charging voltages and vehicles (150 V - 1250 V), thus ensuring the downward compatibility. Conceptually, the interconnection of up to four charging points each 250 kW and the integration of regenerative sources and sinks will also be investigated within the system. The MCS charging system and the associated buffer storage will be set up and evaluated at the Center for Power Electronics and Sustainable Grids at Fraunhofer ISE.