AUTOMOTIVE DESIGN SECTION TITLE
Prototype vehicle and
charging system for 450 kW charging power
RAPIDRECHARGE A
Professor Dr Kai André Böhm discusses the workings of an innovative research project that has achieved 400km range in just 15 minutes
s the availability of Battery Electric Vehicles (BEV) with ranges exceeding 500km continues to increase, the acceptance of
e-mobility is still restricted by lengthy charging durations. Te research project “Direct Superfast Charging for the Electric Vehicle” (abbreviated as “D-See”), funded by the German Federal Ministry of Economics and Climate Protection, aimed to decrease the charging time for 400km of real-world driving performance to just 15 minutes. Over the span of four and a half years,
the participating partners – Bochum University of Applied Sciences, hofer powertrain, innolectric, Keysight Technologies, Sensor-Technik Wiedemann (STW), and Voltavision – have thoroughly analysed and optimised the entire energy flow chain. Tis encompasses everything
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from the power grid to the charging electronics, the charging cable, and finally, the vehicle battery. Te outcome of this research is a fast-charging station with a 450kW charging capacity and a prototype vehicle suitable for reproduction. Together, these advancements enable the energy required to drive 400km to be charged into the vehicle battery in just 15 minutes.
STATE-OF-THE-ART AND PROJECT OBJECTIVES To achieve a range of 400km in real-world driving, a mid-size passenger car requires approximately 88kWh of energy. One of the fastest charging cars globally, if not the fastest, is Porsche’s Taycan 4S. It has the capacity to charge at just under 170kW on average between 0% and 80% state of charge (SoC). However, a maximum charge of 150kW of this power is actually stored
in the battery. Consequently, the Taycan would require at least 35 minutes to charge 88kWh – if its battery were large enough. To charge 88kWh in 15 minutes, a net charge rate of 352kW is necessary, signifying an acceleration of 2.3 times compared to the state of charge. However, this approach comes with a drawback: most losses in the cables, connectors, and the battery are proportional to the square of the current, leading to power losses that are over five times higher. Additionally, every component used had to meet the high project requirements and thus was subjected to rigorous tests in terms of efficiency, cost, comfort, and service life. Existing norms and standards also had to be taken into consideration, including compliance with DIN SPEC 70121. Tis specification outlines the fundamentals of DC fast charging.
RESEARCH AND DEVELOPMENT To enable charging powers of up to 450kW, Keysight Technologies designed new advanced and modular power electronics for the fast-charging process in Silicon Carbide (SiC) technology. With the development of the DC Charging Controller, a fully developed communication unit, the establishment
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