Swiss Startup Winduction Develops Wireless Charging System Integrated Into Bus Tires
The ETH Zurich spin-off claims over 90% energy transfer efficiency by minimizing distance between road coils and vehicle.
Winduction, a Swiss startup and spin-off from ETH Zurich, has developed an inductive charging system for electric buses that integrates receiving coils directly into specially designed tires. The technology aims to reduce transmission distance and improve charging efficiency compared to traditional undercarriage-based systems.
What Happened
Traditional inductive charging systems transfer power from ground coils to vehicle undercarriage coils, but efficiency drops as the distance between the road and the vehicle increases. Winduction addresses this by placing the receiving coils inside the wheels, which are always in contact with the ground. According to CTO Sylvain Fricker, this setup achieves an energy transfer efficiency of over 90 percent from the ground into the vehicle. To make this possible, the company is working with partners to develop steel-free bus tires, as conventional steel belts would react with the magnetic field and generate excessive heat. The system was demonstrated on a bus line between Zurich Airport and the Oerlikon quarter, where calculations suggest that charging plates at only 2 of 24 stops could suffice, reducing total charging time to 3 hours over 16 hours of operation.
Why It Matters
For fleet operators, the potential for higher efficiency and shorter charging intervals could significantly alter cost structures and infrastructure needs. CEO Laurin Schwitter states that regular wireless charging during operation allows for smaller battery packs, which lowers vehicle purchase costs and reduces the number of charging stations required compared to depot charging. A feasibility study with transport operators is currently underway to quantify these savings. The approach could enable electric buses to operate more cheaply by optimizing energy use during brief stops rather than relying on long overnight charging sessions.
The Bottom Line
Winduction is currently building real-world testing infrastructure in Winterthur and plans to conduct its first pilot in 2028. Discussions are ongoing with several Swiss transport operators to bring the tire-integrated charging system to broader commercial use.
