The Japanese manufacturer of electric motors Nidec Corp. has started mass production of the second-generation model (“Gen.2”) of its EV traction motor system, E-Axle in its at Guangzhou, China plant. The new generation is both lighter and quieter than its predecessor. The improvements are achieved through engineering and technological progress in magnetic circuit designing, oil cooling, and other technological knowhow areas, the company says.
In April 2019, Nidec became the first tier-1 company in the world to launch the mass-production of E-Axle, the EV traction motor system that combines a motor, a gear, and an inverter (“Gen.1”) with a maximum power output of 100kW. Since then, a growing number of customers mainly from China have adopted this system their automobiles, with 13 of their models equipped with it as of September 30, 2022. More than 520,000 units have been produced by the date.
E-Axle Gen.2’s is 19% lighter in weight than its predecessor. At the same time, the system offers 20% higher torque and power density thanks to the use of smaller magnetic circuits and inverters based on the second-generation, high-space-factor wire-winding technology. These improvements are also due to the of magnets that require significantly less amounts of dysprosium (Dy), terbium (Tb), and other kinds of heavy rare earth thanks to the improved cooling capability based on the newly developed two-way oil-circulation system. Gradually, Nidec plans to replace these magnets by those free of heavy rare earth. In terms of technology, Nidec’s engineers have overcome a major challenge: At and above a certain temperature (Curie temperature), the power of a magnet is lost. However, the use of dysprosium and terbium makes the magnet more heat-resistant. With the use of better cooling capabilities, Nidec’s E-Axle Gen.2 can successfully decrease magnets’ temperature, thus reducing the required amounts of these materials dramatically.
Motor noise has been reduced by 6 – 8dB compared with the previous model and the one prior to it, both of which were already considered rather quiet, thanks to the optimized component allocation and newly designed gears.
While the 100kW model of E-Axle Gen.2 is now in mass production, the currently produced 200kW, 150kW, and other models in the company’s product lineup will be replaced by Gen.2 gradually.
Gen.2 delivers a peak output: 100kW at a voltage of 350V for 20 seconds. Rated output is 38kW. The peak torque of the output shaft is given as 2,400Nm. The entire system weighs 57kg.
As Nidec aims to acquire 40 – 44% of the global share of the EV drive motor market by 2030, the company’s E-Axle will be the driving force behind this effort, the company announced.