[DigitalToday Seung-a Yoo] General Motors is speeding up efforts to build a U.S. supply chain for key electric vehicle (EV) components. Automotive permanent magnets used in EV motors have begun to be produced in Texas. GM is conducting tests and validation to apply them to EV motors.

On Oct. 19 (local time), EV-focused media outlet CleanTechnica reported that GM is building a supply chain that runs from rare earth mining and refining to magnet production and motor development through long-term cooperation with key materials company MP Materials.

Permanent magnets, a core EV motor component, determine efficiency and power density. GM is currently applying an interior permanent magnet design to most of its EV motors. In that structure, a rotating magnetic field created by the stator interacts with magnets inside the rotor to generate torque. The design offers high efficiency and power density, which helps increase EV driving range and performance and use space efficiently.

However, automotive magnets must withstand high temperatures, vibration and mechanical stress while maintaining stable performance, which makes mass production difficult. GM has improved efficiency by switching magnets used in motors from solid types to segmented types, reducing heat buildup and energy loss.

The companies' cooperation gained momentum in 2021, when GM signed a long-term supply agreement with MP Materials. At the time, MP Materials operated Mountain Pass in California, the only large-scale rare earth mining and refining facility in operation in North America, and was pushing to build an integrated magnet business. GM participated as an early automotive customer for the Independence facility in Fort Worth, Texas.

GM explained that early customers support the process from investment to industrialisation and mass production by securing demand early and aligning long-term plans, while also working through cooperation between technical teams. It said it expected the first magnets to take several years to reach production, but moved forward with the partnership based on the importance of the supply chain and its trust in MP Materials' strategy and technological capabilities.

Now, 5 years after the agreement, MP Materials is producing automotive magnets at the Independence facility. GM is testing and validating the magnets for use in EV motors at its Pontiac research facility in Michigan. The cooperation links rare earth mining and refining in California, magnet manufacturing in Texas and motor development and validation in Michigan. GM presented this as an example of its local production and local sourcing strategy, in which parts are procured where they are produced.

GM's experience in magnet and motor development goes back decades. GM researchers led efforts in the early 1980s to develop production processes for neodymium-based high-performance permanent magnets. Later, the first-generation Chevrolet Volt improved the performance of permanent magnet motors for hybrid cars, and follow-on models adopted a double V-shaped magnet layout to increase torque and reduce noise and vibration. The first-generation Chevrolet Volt EV contributed to applying permanent magnet motor technology to mass-market electric vehicles capable of long-distance driving.

GM stressed that the cooperation is based on more than 30 years of accumulated experience in electric motor development and long-standing innovation in magnet technology. It said strengthening the supply chain requires not only transaction costs but also building long-term partnerships with capable suppliers and making the decision to invest even at stages where uncertainty remains. The cooperation between the two companies is becoming an example of converting a U.S. supply chain spanning rare earth raw materials, magnets and motors into an actual production base.