Renault: Electric motors with no rare earths
Renault is doubling down on electric motors that shun rare earth elements, a strategic move to secure its supply chain and reduce geopolitical dependency. This deep technical dive into their Electrically Excited Synchronous Motors (EESM) highlights years of innovation and future plans for more compact and powerful designs. Hacker News dove into the mechanics of these motors, compared Renault's approach to other manufacturers, and extensively debated the broader geopolitical and supply chain ramifications, especially concerning battery technology.
The Lowdown
Renault Group has been a long-time advocate and developer of electric motors that operate without rare earth elements, positioning itself uniquely in a market dominated by permanent-magnet motors. The company's focus on Electrically Excited Synchronous Motors (EESM) is not just a technical choice but a strategic one, aiming for independence from the global rare earth supply, which is largely controlled by China.
- Motor Technology Explained: The article distinguishes between three primary electric motor types: permanent-magnet synchronous motors (PMM, using rare earths), asynchronous motors (ASM, lower efficiency, often secondary), and electrically excited synchronous motors (EESM, no rare earths, high efficiency). Renault champions the EESM.
- Renault's EESM Journey: Renault first mass-produced EESM motors in 2012 for models like the Kangoo Z.E and Zoe. Their second generation (6A reference) launched in 2021, offering smaller, lighter, and more powerful options (up to 160 kW) for vehicles like the Mégane E-Tech Electric.
- Future Innovations: By 2027, Renault plans to introduce a third-generation E7A motor, promising 200 kW output, a 30% reduction in size and carbon impact, 92% efficiency, and an 800-volt architecture for faster charging.
- Strategic Independence: The core driver for avoiding rare earths is to bypass the supply chain dependency on China, which controls over 90% of global rare earth production and prioritizes its domestic market.
- Local Production: All of Renault's EESM motors, including the upcoming generation, are manufactured at their Cléon plant.
Renault's continued investment and innovation in rare-earth-free motors underscore a significant industry trend towards sustainability and supply chain resilience, aiming to offer competitive performance without geopolitical vulnerability.
The Gossip
Motor Mechanics & Magnet Mastery
Commenters delved into the technical underpinnings of Electrically Excited Synchronous Motors (EESMs), clarifying that they replace permanent rare-earth magnets with controllable electromagnets, often powered by carbon brushes. While this adds complexity and potentially some weight or mechanical robustness concerns, the excitation power draw is described as minor compared to overall efficiency gains. Discussions linked to tear-down videos for visual explanations of the technology.
Competitors & Comparative Capacities
The discussion quickly turned to the competitive landscape, with several commenters pointing out that other manufacturers like BMW and Nissan are also utilizing rare-earth-free motor technologies, sometimes with more advanced specifications (higher power, 800V architecture). It was noted that while common in Europe and India, EESMs are less prevalent in North America and China. The price disparity between Renault and BMW models was highlighted, suggesting these technologies cater to different market segments.
Strategic Supply & Socioeconomic Shifting
A significant part of the discussion revolved around the strategic implications of moving away from rare earths, primarily supply chain independence from China. Commenters speculated on the future pairing of these motors with emerging battery technologies like sodium-ion. However, a counter-argument suggested that geopolitical tensions, export controls, and the EU's industrial policies make such pairings unlikely with Chinese battery manufacturers, pointing instead to Japanese solid-state battery development for these specific supply chains.