800V SiC Technology Drives EV Adoption with Faster Charging

One of the main sticking points in persuading people to migrate to EVs is the time that they take to charge. Owners of ICE vehicles can fill up with petrol or diesel and be back on the road in a matter of minutes, but EV owners generally have to allow a lot more time at the recharge station. When EVs were first becoming popular, 22kW chargers were installed, but the could take hours to get to a convenient charging level, even left charging overnight in some cases. These were often installed in homes and workplaces, where people spend a considerable mount of time. Later “fast charging” 50kW chargers were installed in public areas, but the were still very slow to provide a useable charge.

Now, the latest chargers can be up to 350KW and do a much better job, but those usually require an 800V design to get the quickest charge time. It should be possible to charge a 64kWh battery from 20% to 80% in 7 minutes using an 800V, 350kW charger. Using a practical example, if a Porsche Taycan is connected to a charger that is able to provide 800V and a minimum of 300A, it can be charged from 5% to 80% in 22 and a half minutes. The time it would take a 50kW, 400V charger to do the same job would be around an hour and a half. 800V EV designs also offer more benefits, including allowing a lower current to be used to charge the battery, reducing overheating and providing better power retention, which contributes towards a greater driving range. The smaller motor used by 800V designs also uses less copper, which lightens the design and frees up space for batteries, also increasing the potential range. However, the downsides are that 800V designs have proven more expensive traditionally, and weren’t very practical until SiC technology had matured and new technology was introduced that could cope with the increasing power densities.

Now that SiC devices are more widely understood and used, more and more vehicle manufacturers are moving their designs over to 800V. A new report from IDTechEx highlights how many. The IDTechEx report, “Power Electronics for Electric Vehicles 2022 – 2032” has found that that the transition to silicon carbide MOSFETs and high voltage systems above 800V has been increasing in pace in 2021. Renault, BYD and Hyundai have all announced new 800V vehicle platforms which will adopt SiC MOSFETs in their power electronics. Ford has also joined Tesla, BYD and Toyota in launching an electric car model containing SiC power electronics with the company’s new Mach E.

That transition to 800V designs has brought challenges to module manufacturers with higher switching frequencies, increased power densities, and increased operational temperatures for devices that need a 15-year service life. As the power density of semiconductor chips has been increasing exponentially over the last ten years, double-sided cooling designs, copper wire bonds, and lead frames have been required to allow the designs to be practical. Nano silver-sintered materials and copper sintered materials have also been adopted thanks to their high melting points compared with traditional tin-based lead-free solders.

The technology is now in place to allow more vehicle manufacturers to migrate to 800V designs that have the ability to offer increased range and faster charging, making the vehicles much more attractive to potential buyers.

www.IDTechEx.com/Power