Many automakers have invested heavily in the research and development of non-rare-earth motors, and some have already achieved successful mass production in certain areas. However, in terms of motor performance, power density, and technological maturity, the advantages of rare-earth motors remain very clear.
Rare-Earth Motors
In the automotive sector, rare earth motors still hold a dominant position due to their inherent advantages.
| High Efficiency: Rare-earth permanent magnet motors do not require electrical excitation and have no rotor copper losses, with energy conversion efficiencies generally exceeding 95% (some high-end models achieving even higher). They maintain high energy efficiency even under light load and variable load conditions.
| Compact Size and Lightweight:
Rare-earth permanent magnets have a high magnetic energy density, allowing motors to be more than 20% smaller and significantly lighter at the same power and speed. This helps reduce the overall weight of the equipment, improve range, and save installation space.
| Simplified Structure and Low Maintenance Costs: Rare-earth motors use electronic commutation, eliminating the carbon brushes and slip rings found in traditional motors. This reduces mechanical friction losses and wear components, resulting in a lower failure rate, significantly reduced maintenance costs, and more reliable operation.
Non-Rare Earth Motors
Iron Nitride Motors
Iron nitride motors can achieve efficiencies close to that of rare-earth permanent magnet motors at 98%, and the cost of raw materials can decrease by 10-15%. However, iron nitride motors still cannot replace rare-earth motors.
| The reliability of iron nitride materials is insufficient; once the operating temperature exceeds 150°C, significant demagnetization occurs, whereas rare-earth permanent magnets can withstand temperatures above 200°C. Additionally, if iron nitride is exposed to air, it reacts with oxygen, leading to demagnetization, so strict sealing is required for the motor casing.
| Moreover, the manufacturing process of iron nitride is complex, requiring physical vapor deposition to grow on specific substrates. It is crucial to precisely control the nitrogen partial pressure and substrate temperature, maintaining the ratio of nitrogen atoms to iron atoms within a specific range; any slight deviation can cause a sharp decline in magnetism. Even in laboratory settings, only a few grams of performance-compliant iron nitride samples can be produced per hour, far from meeting large-scale production demands.
Ferrite Motors
The cost of ferrite motor systems is only about 30% of that of rare-earth motors. However, ferrite motors are primarily applied in commercial vehicles and cannot be extended to passenger vehicles due to obvious drawbacks.
| At the same power levels, ferrite permanent magnet motors are usually 10-30% larger than rare-earth motors, often failing to meet the compact layout requirements of passenger vehicle front compartments.
| Due to the low magnetic force of the rotor, ferrite permanent magnet motors struggle to reach the high speeds of rare-earth motors. Typically, their efficiency drops significantly when ferrite motors reach 15,000 RPM, making it difficult to meet the demands of prolonged high-speed cruising.
Magnets Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Caranddriver & Chargedevs & Emworks & Magnetstek & Stanfordmagnets
