High-temperature resistant magnets: The engineering cornerstone for the performance and reliability of automotive BLDC motors

In the wave of automotive electrification and intelligence, BLDC brushless DC motors have become the core force driving technological progress, whether as the main power source of vehicles or to drive key systems such as power steering, water pumps, and fans. When we talk about the efficiency, power density and reliability of BLDC motors, behind their outstanding performance lies the support of a key material - high-performance high-temperature resistant magnets. It has evolved from a functional component into an engineering cornerstone that determines the performance ceiling and long-term stability of motors.

For automotive engineers, one of the most severe challenges that BLDC motors face is high-temperature environments. When a motor operates at high speed and under high load, it generates a large amount of heat, and its own temperature can easily rise above 150°C or even 200°C. However, for common permanent magnets, such as neodymium iron boron of regular grades, their magnetic properties will significantly decline at such high temperatures, resulting in a decrease in motor output torque and efficiency. In more severe cases, irreversible demagnetization may occur, directly threatening driving safety.

This is precisely the value of high-temperature resistant magnets. By adding heavy rare earth elements such as dysprosium and terbium and conducting advanced grain boundary diffusion processes, the coercive force - that is, the ability to resist demagnetization - of these special neodymium iron boron magnets has been significantly enhanced. This means that even in extremely high temperatures, they can firmly "lock" the magnetism, ensuring the stability of the motor‘s magnetic field, thereby guaranteeing that the vehicle can still output continuous peak power after intense driving or long-term operation. It can be said that choosing the correct grade of high-temperature magnets (such as SH, UH, EH) is the first step in designing a Robust automotive BLDC motor.

In addition to ensuring instantaneous performance, the thermal stability of high-temperature resistant magnets is the key to the long-term reliability of motors. Throughout the entire vehicle life cycle, the motor will undergo countless thermal cycles. Ordinary magnets will experience irreversible loss of magnetic flux after repeated heating and cooling, leading to a slow decline in motor performance. High-quality high-temperature resistant magnets can minimize such losses to the greatest extent, ensuring that after eight or ten years, the feel of the electric power steering remains stable and the power response of the drive motor is still prompt. This long-term performance consistency is crucial for maintaining brand reputation and user trust.

From a more macroscopic perspective, high-temperature resistant magnets remain the core driving force for achieving lightweight motors and high power density. Because it can withstand higher operating temperatures, engineers dare to use a higher current density to drive the motor, thereby squeezing out greater torque and power in a smaller volume. This not only directly increases the driving range of electric vehicles, but also leaves more valuable space for the overall vehicle layout.

In conclusion, the role of high-temperature resistant magnets is far more than just "not demagnetizing". It is the unsung hero that empowers BLDC motors to perform stably and remain durable on the demanding stage of automobiles. With the popularization of new technologies such as 800V high-voltage platforms and silicon carbide electric drives, the working environment of motors will face more extreme temperature tests. In the future, the pursuit of magnets with higher operating temperatures and lower heavy rare earth content will surely continue to drive the integrated innovation of materials science and automotive electrical engineering, jointly driving the future of electric mobility.