Magnetic materials are magnetically ordered materials that exhibit ferromagnetic or antiferromagnetic properties and have practical application value. A fundamental distinction between them and other materials is their sensitivity to external magnetic fields. In a broader sense, magnetic materials also include antiferromagnetic materials and other weakly magnetic materials that have practical or potential application value.
In recent years, overall demand in the magnetic materials industry has risen steadily. The rapid development of downstream application sectors—such as photovoltaic storage, wind power, new energy vehicles, robotics, industrial automation, and wireless charging—has created significant growth opportunities for the industry.
I. Performance Metrics for Magnetic Materials
The performance metrics for magnetic materials are as follows:
1. Stability: The primary parameters are residual magnetization and maximum energy product. Higher values indicate a stronger magnetic field and a greater ability of the magnet to maintain its magnetic properties.
2. Demagnetization Resistance: The primary parameter is intrinsic coercivity. Higher values indicate stronger resistance to demagnetization and higher operational efficiency.
3. Temperature Stability: The primary parameters are intrinsic coercivity, maximum operating temperature, and Curie temperature. Higher values indicate better temperature resistance and more stable magnetic material performance.
II. Classification and Applications of Magnetic Materials
Based on their functions, magnetic materials can be divided into three major categories: permanent magnet materials, soft magnetic materials, and functional magnetic materials.
Currently, the materials most commonly used in new energy vehicles include neodymium-iron-boron (Nd-Fe-B) permanent magnets and ferrite permanent magnets among permanent magnet materials, as well as silicon steel, metal soft magnetic powder cores, and ferrite soft magnetic materials among soft magnetic materials.
1 Permanent Magnet Materials—Neodymium-Iron-Boron
Neodymium-iron-boron (Nd-Fe-B) permanent magnet materials, primarily composed of Nd₂Fe₁₄B, feature high residual magnetism and high coercive force. These materials offer superior performance, significantly improving motor energy efficiency and reducing energy loss.
Each new energy vehicle requires approximately 2.5 kg of neodymium-iron-boron permanent magnet material, which is primarily used in components such as drive motors, ABS, and EPS. In addition, in-vehicle speakers and various sensors are other applications of neodymium-iron-boron permanent magnet materials in new energy vehicles.
2 Permanent Magnet Materials—Ferrite
Ferrite permanent magnet materials are manufactured using ceramic processes with SrO or BaO and Fe₂O₃ as raw materials.
Compared to rare-earth permanent magnet materials, although ferrite permanent magnet materials do not have a performance advantage, they remain the material of choice in many fields due to their abundant raw materials, low cost, simple manufacturing process, excellent oxidation resistance, and high residual magnetization. In new energy vehicles, they are primarily used in components such as drive motors, converters, and charging stations.
3 Soft Magnetic Materials—Silicon Steel
Silicon steel is an iron-silicon alloy formed by adding a small amount of silicon (generally less than 4.5%) to pure iron. It possesses excellent electromagnetic properties, including high magnetic permeability, low hysteresis loss, and low iron loss. In new energy vehicles, silicon steel is one of the key materials used in electric motors; it effectively reduces iron loss and hysteresis loss, thereby improving motor efficiency and performance. In addition to motors, silicon steel is also used in charging stations, battery management systems, and body structural components for new energy vehicles.
4 Soft Magnetic Materials—Metal Soft Magnetic Powder Cores
Metal soft magnetic powder cores are soft magnetic materials formed by compressing magnetic powder coated with an insulating medium. They combine the advantages of metal soft magnetic materials and soft magnetic ferrites. Since the powder consists of ferromagnetic particles, they have a high saturation magnetic flux density; at the same time, due to the presence of the insulating layer, they also have a high resistivity.
They are primarily used in three application areas within the new energy vehicle sector: charging stations, on-board AC/DC chargers, and on-board DC/DC converters. Particularly with the trend toward 800V high-voltage platforms, metal soft magnetic powder cores are expected to benefit significantly, with per-vehicle usage projected to increase from the current level of approximately 0.7 kg to 2.7 kg.
5 Soft Magnetic Materials—Ferrite
Soft magnetic ferrite is a paramagnetic oxide primarily composed of Fe₂O₃ and produced using powder metallurgy methods. There are several types, including Mn-Zn, Cu-Zn, and Ni-Zn, among which Mn-Zn ferrite has the highest production volume and consumption.
As a functional electronic material with excellent high-frequency electrical properties, relatively low cost, and ease of processing into products of various shapes and sizes, soft magnetic ferrites are widely used in new energy vehicle on-board chargers (OBCs), EV charging equipment, power conversion in HEV powertrains, DC-DC converters, battery management systems, and power distribution units.
III. Application Prospects for Magnetic Materials in New Energy Vehicles
As the foundational core material for key electronic components, magnetic materials are extensively used in various aspects of automotive motors, vehicle bodies, chassis, and information systems, playing an increasingly important role in the development of the automotive industry. According to statistics, an automobile typically consists of approximately 20,000 parts, of which several thousand are magnetic components.
