Multi-speed electric drive units from ZF make a case for transmissions in electric vehicles

Renowned automotive supplier ZF has announced that it will build modular powertrains for light-duty electric vehicles, which it plans to make available starting mid-decade. They’re improvements on the first-generation units in many ways, but the integration of transmissions comes as the biggest philosophical shift in the industry’s approach to electric vehicles.

ZF says the units, which it calls “e-drive,” are intended to be built in three basic configurations for passenger cars and light commercial vehicles. (In other words, vehicles you’ll see in everyday life.) The units consist of a motor, inverter, controllers, transmission, and software, each optimized to reduce cost, size, and improve performance.

ZF claims to have improved power density using oil flow cooling, increasing the continuous power rating of the units to 85% of their peak power. This allows the motors to use more of their potential on a regular basis, allowing smaller motors to handle heavier applications, increasing efficiency. ZF says that using braided windings in motors reduces their volume by about 10 percent, and material use by the same amount. Its design also allows it to significantly reduce the use of heavy minerals and expensive rare earths.

ZF presents the various configurable options for its “e-drive” unit. ZF

Further performance improvement and efficiency are integral planetary gears; the magic that makes automatic transmissions work. ZF would know a thing or two about transmissions. They will offer a combination of forward and reverse gears, just like the Porsche Taycan and the Mercedes-Benz EQG off-roader prototype with their two-speed drive units. The gear sets are also designed to work as a differential, although it is not clear if there are separate planetary gears for each axle. If so, that could allow the axles to rotate in opposite directions for a feature similar to Rivian’s Tank Turn (unreleased). However, the efficiency gains offered by multi-speed transmissions are by far the biggest selling point.

ZF says it plans to have its “e-drives” on the market in 2025 and claims it already has an order book equivalent to nearly $26 billion. The drive components are said to go into production earlier and be available individually. Since ZF is more of an industry supplier than a consumer-oriented business, they are unlikely to be available for small car purchases.

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