Shorter charging times for battery-electric vehicles can be achieved with a modified electrical system architecture: The high-voltage electrical system - especially in e-cars in the premium and sports car segments - is designed for a voltage of 800 V instead of 400 V as in the past.
For this purpose, ZF develops and produces corresponding components for the electric driveline. The focus here is on silicon carbide power electronics. This technology is already being used by ZF in the Formula E racing series and is to be launched on the market in several upscale vehicles this year.
»It is becoming apparent that the 800-V architecture will establish itself in future premium vehicles or sports electric vehicles, whereas the 400-V architecture will remain the standard in the volume market,« says Bert Hellwig, responsible for system development of electric drives at ZF. »For 400-V applications, we have already been supplying series technology for years; for 800-V applications, we are now preparing the start of series production for this year.«
When it comes to the user-friendliness of e-vehicles, charging time plays an important role. If electric cars are to be suitable for long-distance travel, the battery must be almost fully charged again within an hour. The fundamental problem with fast charging: If higher currents flow, thicker cables must be used or better cooling must be provided because more heat is generated. This increases the weight of the vehicle and the complexity of the charging infrastructure - unless the on-board network architecture is designed for higher performance from the outset. That's why many automakers are planning upcoming production vehicles with the higher voltage of 800 V.
»We are currently working on the start of series production for several 800 V projects,« Hellwig reveals. »For several models from a Chinese manufacturer, we are supplying the complete electric powertrain, including power electronics. And for a European sports car manufacturer, ZF is contributing the power electronics for a high-voltage application.« Further production start-ups are already on the horizon. »When designing the power electronics for 800 V, we can expand synergies between passenger cars and other applications,« Hellwig adds.