New Materials for an Electric Vehicle Magnet.
ST Magnetic

Professional and reliable supplier of customized magnets

New Materials for an Electric Vehicle Magnet

An Electric vehicle magnet is a vital component in motors for EVs (electric vehicles) and hybrids. The magnets provide the magnetic force needed to turn the rotor, which in turns drives the electric motor’s shaft, and also the torque needed for speed control. The magnet must be strong enough to support the weight of steel — as heavy as prizefighter Tyson Fury, for example — yet still be small and lightweight. It must also be able to withstand high temperatures, as the electric motors used in EVs are often run at more than twice the normal operating voltage of traditional automotive engines.

Currently, neodymium iron boron (NdFeB) magnets are considered the optimum for use in EV motors. They offer the best combination of magnetic force, heat/temperature withstand parameters and size. However, the demand for EVs is putting a strain on the supply of NdFeB magnets. As a result, the price of neodymium has doubled in the past two years, making it more expensive to produce an EV.

One solution is to make EVs with permanent magnet motors instead of induction motors. However, that would increase the cost of the motors, and the loss of power generated by core losses and iron losses — as well as hysteresis — could reduce efficiency and reliability.

Another alternative is to use electro-magnets in the rotor instead of permanent magnets. However, those magnets require a power supply to operate, which impacts efficiency by 1-3pp, and they are vulnerable to degradation of the brushes that feed power to them. In addition, they generate heat from hysteresis and have poor performance at low speeds, when most driving takes place.

Lastly, using magnets with lower coercivity could significantly increase the amount of energy lost in the system. This is because the magnets will degrade much faster under these conditions. The good news is that a new material can be used to decrease the coercivity of NdFeB magnets and increase their life span under normal operating conditions.

Moreover, there are several companies developing new materials that can replace the rare earth elements used in EVs’ magnets. For instance, Toyota is working on a new neodymium-reduced magnet that’s both stronger and more heat-resistant than NdFeB. The company hopes to have it in production by 2023.