China and UK develop wireless EV charging with 98.51% efficiency

A joint Chinese-British team built a 20 kW wireless charging system for electric vehicles with a record 98.51% AC-to-AC efficiency and 9.55 kW/L volumetric power density. It replaces ferrite cores with stress-annealed Fe-based nanocrystalline alloys, cutting the core to just 4 mm thick. The technology targets autonomous robotaxi fleets, factory AGVs and electric aircraft.

• AC-to-AC efficiency reaches 98.51% at 20 kW output
• Magnetic core measures 440×330 mm and just 4 mm thick
• Core losses cut to 135 kW/m³ at 85 kHz and 0.2 T
• Targets robotaxis, factory AGVs and low-altitude electric aircraft