Neodymium magnets in electric motors

The Power Hidden in Magnets... Permanent Magnet Synchronous Motors

In PMSM (Permanent Magnet Synchronous Motor) designs, neodymium magnets placed on the rotor replace traditional windings. This is a revolutionary design change that eliminates the need to supply current to the rotor, thereby eliminating so-called excitation losses.

Why do engineers choose neodymium (NdFeB)?

• Maximum Efficiency: No heat loss on the rotor means more battery energy is converted directly into wheel movement. This is key to increasing the range of an electric vehicle (EV).
• Mass Reduction (Power-to-weight ratio): Thanks to the massive magnetic energy density of neodymium, the motor can be up to half the size and weight of traditional induction designs of the same power.
• Dynamics: A constant, strong magnetic field guarantees high torque availability from zero RPM, translating into instant acceleration.

Challenges associated with lithium-ion batteries

Lithium-ion (Li-ion) batteries are the dominant type of batteries used in electric vehicles due to their high energy density, long lifespan, and relatively low weight. However, Li-ion batteries also have their drawbacks.

Fire hazards

In the event of mechanical damage, overheating, or excessive charging, Li-ion batteries can undergo thermal runaway - a chain reaction that leads to explosion and intense fire. Li-ion battery fires are difficult to extinguish because the internal chemistry releases oxygen, which sustains the flames. Therefore, such fires can last up to 24 hours and are challenging to control.

Disposal challenges

Li-ion battery recycling is the biggest engineering challenge in the EV industry, often referred to as Urban Mining. Unlike simple lead-acid batteries, a lithium cell is a complex chemical 'sandwich' requiring advanced technologies to dismantle.

Real challenges and solutions:

• Material Separation: The main difficulty lies in the binders connecting the cathode to the anode. Traditional thermal methods are energy-intensive, which is why the industry is shifting towards hydrometallurgy – a chemical process allowing for up to 95% raw material recovery.
• The Battle for 'Black Mass': The goal of recycling is the recovery of so-called Black Mass – a powder rich in lithium, cobalt, nickel, and manganese. It is these elements, rather than disposal itself, that make the process economically viable.

Prospects and future development directions

In response to these challenges, scientists and engineers are exploring alternative solutions for both neodymium magnets and lithium-ion batteries. Research efforts are focused on developing magnetic materials with lower rare earth element content, such as iron-nitrogen (FeN) magnets, and on developing more efficient and safer battery technologies, such as lithium-polymer, lithium-silicon, or lithium-sulfur batteries.
Neodymium magnets have played a key role in the development of electric motors used in electric cars, contributing to increased efficiency and power density. At the same time, lithium-ion batteries, being a crucial component of electromobility, bring challenges related to fire hazards and disposal. Further research is necessary to develop new, more durable, and eco-friendly solutions for future generations of electric vehicles.

Li-ion battery memory

Lithium-ion batteries have a unique characteristic known as the "memory effect", but it is significantly less pronounced compared to older technologies such as nickel-cadmium (NiCd) or nickel-metal hydride (NiMH) batteries. The memory effect implies that a battery can "forget" its full capacity if it is frequently charged before being completely discharged. However, in the case of lithium-ion batteries, the memory effect is minimal, allowing users to partially charge them without significantly impacting the battery's lifespan.