DeepDrive Skateboard: More Efficiency Through Wheel Hub Drive

Ten years ago, some students from the Technical University of Munich (TUM) worked on building electric racing cars as part of the university’s motorsport team. After graduating and spending some years at e-mobility companies, those racing car builders have reunited to found DeepDrive. Their goal is to rethink electric vehicles.

From XS to L

The result is a four-stage platform modular system designed to cover all needs. The smallest platform, XS, with a power output of up to 30 kW and a range of 350 kilometers, is meant for L7e vehicles, mini shuttles, and last-mile delivery vans. The S base for passenger cars and small transporters will have up to 150 kW of power and around 450 kilometers of range. Above that are the M and L platforms, with up to 250 kW of power and targeted ranges of 600 and 700 kilometers, respectively. The speed for the XS platform will vary between 45 and 80 km/h depending on use. Skateboard S, M, and L will be limited to 160 km/h.

More efficient than conventional platforms

Weight reduction was a primary objective of the Munich start-up. In the DeepDrive platform, the wheel hub motors replace the mechanical brake system on the rear axle, the conventional axle, and the drive shafts, resulting in a weight reduction of about 70 kg. Additionally, in an electric vehicle with a range of 500 km, the battery capacity can be reduced by about 10 kWh for the same range, resulting in a further weight reduction of 60 kg. This weight reduction of 130 kg reduces the vehicle's rolling resistance. The higher efficiency of the wheel hub motors compared to a conventional electric drive and the reduction of friction losses in the drive shaft, axle, and transmission lead to significantly higher vehicle efficiency.

In addition, the free space in the rear provides additional design freedom to reduce the energy consumption of electric vehicles. For example, it could be used to improve the vehicle's aerodynamics.

The Problem of Unsprung Mass

The smaller the unsprung mass in relation to the sprung mass, the less the undesirable fluctuations in wheel load and body accelerations affect driving performance. One kilogram of unsprung mass has the same impact on driving behavior as about seven kilograms of sprung mass. DeepDrive aims to address this problem with consistent lightweight construction and by saving the weight of the mechanical brake on the drive wheels. However, how well this can be achieved in practice remains to be seen. It’s no coincidence that manufacturers of particularly agile cars try to minimize unsprung mass with lightweight construction in rims and brakes.