Electric powertrain architectures in commercial vehicles are moving away from conventional central drive layouts toward more integrated and modular solutions. Among these, integrated electric drive axles and distributed electric drive systems are emerging as the two dominant technical routes.
For electric buses and trucks, the choice between these architectures has a direct impact on vehicle layout, efficiency, cost structure, and long term operational performance.
An integrated electric drive axle combines the electric motor, transmission, differential, and in many cases the inverter into a single compact unit. By eliminating the need for a separate gearbox and drive shaft, this architecture shortens the power transmission path and reduces mechanical losses.
For bus platforms, this compact integration frees up chassis space for battery placement, supports higher driving range, and simplifies vehicle layout. The reduced component count also improves system reliability and lowers maintenance complexity, which is critical for high utilisation fleets.
As a result, integrated electric drive axles have already seen wide adoption in electric light trucks and are increasingly becoming the preferred solution for urban and intercity electric buses.
Distributed electric drive systems place motors at or near the wheels, either as wheel side motors or hub motors. This configuration enables independent wheel control, improved manoeuvrability, and advanced functions such as differential steering.
While these features are attractive, particularly for specialised applications, distributed systems introduce higher technical complexity. They require extremely high torque density, precise motor control, advanced thermal management, and robust sealing to withstand harsh operating environments.
Cost and durability remain key challenges, especially in heavy duty bus applications where long service life and predictable maintenance are essential. As a result, distributed drive systems are currently more common in niche or high end vehicle segments rather than mass deployment.
From an OEM perspective, integrated electric drive axles offer a pragmatic balance. They deliver high transmission efficiency, support regenerative braking, and align well with existing axle based vehicle architectures. Their scalability across different vehicle weights and duty cycles makes them particularly attractive for bus platforms operating in diverse conditions.
While distributed drive solutions continue to evolve and may play a larger role in future vehicle concepts, integrated electric drive axles currently represent the most mature and commercially viable architecture for electric buses and commercial vehicles.
