Electric motor technology. Major trends and implications

An eclectic mix of increasing sustainability initiatives, growing customer demand, rising research into electric powertrain components, and favorable regulatory policies is driving the alternative propulsion (AP) technologies on full throttle.

The global AP market (which includes MHEV, FHEV, BEV, and FCEVs) is forecast to grow at a rapid pace, with governments and legislative bodies around the world driving the adoption of green technology through legislation.

With the technological advancements in battery chemistry, increasing investment commitments in electric powertrains, and the entry of new and emerging players, the BEV space has witnessed phenomenal growth. EVs accounted for about 25% of the alternative powertrain market in 2020 and are forecast to account for more than 35% of the alternative powertrain market by 2030, which is projected to increase at a 17% compound average growth rate (CAGR) during 2020–30.

Components of the electric powertrain add complexity to the powertrain architecture when used individually. For instance, e-motor and power electronics require additional circuits for thermal management. The integration of electric powertrain components into a single package to create compact, lightweight, and efficient solutions providing superior performance and efficiency, is the most preferred solution in the full hybrid and battery electric vehicles. Considering the benefits they offer, e-axles are expected to remain the dominant technology for BEVs, accounting for more than 80% of the electric motors used for the production of BEVs in 2030.

The global e-axle motor market is forecast to grow from 3.5 million units in 2020 to almost 25 million units in 2030, a prolific CAGR of about 20%. This represents a significant market opportunity for all areas of the electric motor supply chain: electrical steel producers, copper winding producers, and aluminum casters.

Among all the motor solutions that might be used within e-axle, permanent magnet (PM) motors have been the preferred motor type solution, owing to their higher efficiency and compact construction. The PM motors offer higher torque density, better efficiency, a smaller packaging envelope, and significant performance advantages when operating over a wide drive cycle, making PM motors the preferred choice, even though other solutions, as induction machines, have a lower manufacturing cost and do not use rare-earth magnets.

While OEMs and suppliers continue to develop and use alternative motor topologies, IHS Markit still forecasts that more than 70% of the 2030 e-axle vehicle market will utilize PM motors designs.

The primary challenge associated with PM motors is the use of rare earth magnets providing higher flux density (NdFeB and SmCo magnets) in the rotor, of which there are significant concerns about their pricing variability and the reliability of the supply chain. Given the rapid increase in the demand for the REEs and limited global supply, automakers have to be on the lookout for swift changes in the rare-earth mineral cost or a supply shock similar to the battery cell and semiconductor chip shock experienced by OEMs recently.

Compared to the PM motors, Induction motors are cost-effective to manufacture, very reliable, and generate good low-end torque. Unfortunately, they are not as efficient at converting electrical energy into mechanical energy as is the IPM topology. As these motors do not require the use of expensive rare-earth magnets, automakers see AC induction motors as economical solutions for EV traction applications. The induction motor is used on the front axle of both the Tesla Model S and the Audi e-tron.

There is a growing trend in EV global standard platforms for AWD and 4WD BEVs (Battery Electric Vehicles) to use a PM machine on one axle while offering an induction motor on the second axle as a performance upgrade. In this configuration, while the PM machine is used to provide steady traction once desired speed is reached, the IM machine acts as a boost motor to improve vehicle acceleration. This approach has already been applied to the Tesla Model 3 and will also be utilized on all the new BEVs to be produced on the Volkswagen Group’s MEB platform as well as General Motors’ BEV3 platform.

In the longer term, beyond 2030, as concerns towards the vehicle range reduce and as the charging infrastructure becomes relatively omnipresent, the need to have an efficient powertrain configuration may reduce. The development, coupled with the fact that the reducing battery prices may enable OEMs to add additional battery capacities to make up for the lost powertrain efficiency, leads to a lesser reliance on the PM technology, and OEMs can be witnessed adopting IM or other relatively lesser used motor technologies. Induction motors have traditionally utilized aluminum in the rotor; however, there is an opportunity to introduce copper as a replacement to improve motor efficiency.

Apart from the mainstream motor technologies used for e-axle applications, the market has witnessed the emergence of new motor technologies as well. Current excited wound rotor synchronous motors are already in production at Renault, and the next generation BMW Heat e-Axle also uses this design. These applications may be of interest since there is copper content on both the rotor and stator. The Axial-Flux Permanent Magnet design (AFPM) is also well known for its Ferrari SF90 application. However, IHS Markit does not expect any significant disruptive trends in the light passenger automotive e-motor markets in the short to medium term. Nevertheless, there are considerable opportunities to use alternative motor topologies for traction motor applications outside of the light passenger market, such as for commercial vehicles, construction equipment, and in the agriculture domain.

Some suppliers are investigating the viable usage of in-wheel motors. This application can increase the drive-train efficiency by removing the transmission system losses, allowing torque vectoring, liberating interior space, and potentially lowering and widening the cargo area. Despite the advantages, aspects related to component durability and vehicle dynamics due to the addition of unsprung weight and thermal challenges still require attention. Although certain electric vehicle platforms have successfully adopted the in-wheel motor configuration, mainstream OEMs are not expected to adopt the technology in the short to medium term.

One of the megatrends that are expected to have a significant influence on the e-axle motor market for light vehicles is the shift in the supply chain dynamics. IHS Markit expects mainstream automotive brands to increase their respective in-house production of e-motors over the next few years with different modalities on a regional basis. For example, around 60% of e-Axle motors made in 2025 are forecast to be developed in-house. This will grow to two-thirds of the component’s global production by 2030.


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