Leading Japan-based motor manufacturer Nidec is relentlessly pursuing future topologies for e-propulsion along with mass production capabilities for its growing lineup of e-axles. The progress was evident in its forward-leaning display at Techno-Frontier 2025 motor technology expo, held during the end of July at Tokyo Big Sight convention center. Systems for electric vehicle mobility dominated the presentation but new strategies for aircraft and motor testing were highlighted as well.
Among the latest advancements are:
- a third-generation e-axle that is the first 7-in-1 system whose mass production has begun
- a fourth-generation e-axle currently in development with better functions and mountability
- a next-generation, magnet-free, high-performance e-axle currently currently in development
- new motors for EVTOL and drone aircraft
- electronic speed controllers equipped with advanced power semiconductors
Figuring that people will own 300 to 600 million EVs globally in 2030, Nidec targets to achieve a global market share of 40-45% with its e-axle by then. In pursuit of that goal, it has been accelerating research and development along with manufacturing capability, as previously reported in Magnetics Magazine, to quickly build traction motor mass-production systems globally. Already the lineup includes models that cover all segments of electric vehicles ranging from compact cars to large SUVs.
The models are overwhelmingly more compact and lighter than gasoline engines of the same classes, while boasting high torques and output densities. The product development continues to push boundaries. Its second-generation units, for example, brought a torque and an output density 20% better, and a weight 19% lighter, than its first-generation predecessor.
Densifying the stator core’s winding wires
Improving a motor’s efficiency requires densifying the winding wires of its stator, which is the source of torque. For its first-generation models, Nidec developed a new method of inserting a cassette of winding wires for better density (the “cassette inserter” method), to achieve both a high production efficiency and an improved slot-filling factor. Furthermore, for the second-generation models, Shapes of the stator cores have been revised to accommodate winding wires, and reduced the load of coils inserted into slots, while adopting the company’s unique wire-winding machines, to improve the coil share per slot section area.
Significant Reduction of Heavy Rare Earth Usage
Heat-fighting measures are essential in improving motor efficiency, notes Nidec. As heat affects the motor’s operating times and duration of time, the more output a motor generates, the more important its cooling unit becomes. In particular, a rotor’s permanent magnets, which generate electromagnetic force after interacting with a stator, can exhibit a characteristic of the magnetic force weakening above a certain temperature. To counter this, for its first-generation products, Nidec would produce an oil-based cooling route on the inside and outside of each motor, to directly pour oil over a heated section to cool it, while, for permanent magnets, increasing the content of heavy rare earth to improve their thermos-tolerance.
The latter, though, had a demerit of increasing product costs. So Nidec engineers improved the cooling method for second-generation E-Axle units, using a nozzle to spray oil cooled in an oil cooler to cool the stator from the outside. To improve the cooling performance further, they designed a system to spray oil by using the rotor’s centrifugal force to pour oil on the magnet, the rest of the rotor and the stator coil. The improvements enabled driving the motors stably under a rated output even after employing a heavy rare earth-free magnet to a rotor.
For more info, see www.nidec.com.
