Why are Small Foreign Metal Particles (SFMPs) a concern in electronic devices?

Small Foreign Metal Particles (SFMPs) pose a risk because, when present in high-performance chemical films (HPCFs) used in components like lithium-ion batteries, they can lead to overheating. This overheating can result in battery failures, fires, or even explosions, compromising the safety and reliability of electronic devices.

How does the induction heating (IH) system detect microscopic metal particles?

The system works by using induction heating (IH) coils to generate a high-frequency magnetic field. When an SFMP enters this field, eddy currents are induced within the particle, causing it to heat up. A thermographic camera then detects this heat, revealing the location of the SFMP.

How is JSOL JMAG software used in the design of the induction heating coils?

JSOL JMAG software is used to optimize the design and performance of the induction heating (IH) coils. It is a powerful electromagnetic field simulation tool that allows researchers to model and refine the coil design. This ensures that the magnetic field is focused effectively, maximizing the heating effect on the Small Foreign Metal Particles (SFMPs).

What happens after the metal particles are detected, and how are they removed from the high-performance chemical films (HPCFs)?

While the advancement focuses on detection using induction heating (IH) coils and a 400 kHz SiC-MOSFETs inverter system, the article doesn't detail the exact methods for removing these detected Small Foreign Metal Particles (SFMPs) from High-Performance Chemical Films (HPCFs). However, it's implied that identifying and locating the particles is the critical first step, which would likely be followed by a cleaning or filtration process to eliminate the contaminants. The next step would be to implement preventative measures during the manufacturing process of HPCFs.

Microscopic metal particles glowing within a battery, detected by a thermographic camera.

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Q: What role does the 400 kHz SiC-MOSFETs inverter play in the SFMPs detection system?

The 400 kHz SiC-MOSFETs inverter is crucial because it provides the high-frequency power necessary for effective induction heating of the microscopic metal particles. SiC-MOSFETs (Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistors) are used due to their ability to handle high frequencies and power levels efficiently. Operating at 400 kHz allows the system to induce sufficient heat in even the smallest SFMPs for detection.

Kai Mendoza in Tech & Innovation September 2025 • 4 min read.

"Unveiling the Innovative Induction Heating Coils and SiC-MOSFETs Inverter System for Detecting Small-Foreign-Metal Particles (SFMPs)"

Imagine a world where the tiniest speck of dust could cripple your smartphone, laptop, or even your electric car. It sounds like science fiction, but in reality, the presence of microscopic foreign metal particles (SFMPs) in high-performance chemical films (HPCFs) poses a significant threat to the reliability and safety of many electronic devices we rely on daily. These films are integral to lithium-ion batteries, the workhorses of modern electronics, and even the displays of our beloved gadgets.

These SFMPs, often stainless steel, originate from the machinery used to manufacture HPCFs. Even though manufacturers take precautions, these particles, sometimes as small as 0.1 mm, can adhere to the films. The real danger arises when these batteries overheat, potentially causing fires or explosions. Ensuring the safety of these products requires the ability to detect these microscopic intruders.

Scientists at Yamaguchi University in Japan are tackling this problem head-on with an innovative solution: a high-frequency induction heating system. This technology uses specially designed induction heating (IH) coils and a 400 kHz SiC-MOSFETs inverter to detect these hidden metal particles. This groundbreaking approach promises to enhance the safety and reliability of electronic devices.

Induction Heating: The Key to Unmasking Microscopic Metal Particles

Microscopic metal particles glowing within a battery, detected by a thermographic camera.

The core of this new technology lies in the innovative use of induction heating. Induction heating is a process where a material is heated without direct contact using electromagnetic induction. In this system, specialized IH coils generate a high-frequency magnetic field. When an SFMP enters this field, it heats up due to induced eddy currents.

The system operates at 400 kHz using SiC-MOSFETs (Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistors). SiC-MOSFETs are preferred due to their ability to handle high frequencies and power levels efficiently. This high-frequency operation is crucial for effectively heating the tiny metal particles.

E- and I-Shaped Ferrite Cores: The IH coils are constructed using E- and I-shaped ferrite cores. These cores focus the magnetic field, maximizing the heating effect on the SFMPs.
JSOL JMAG Software: The design and performance of the IH coils are optimized using JSOL JMAG software, a powerful electromagnetic field simulation tool. This software allows researchers to model and refine the coil design for maximum efficiency.
Thermographic Camera: A thermographic camera is used to detect the heated SFMPs. This camera captures the infrared radiation emitted by the particles, creating a thermal image that reveals their location.

The researchers theoretically calculated that the system could raise the temperature of a 0.15 mm stainless-steel ball (SUS304) by 5°C in just 5 seconds. This temperature increase is sufficient for the thermographic camera to detect the particle. To validate these calculations, they constructed a prototype SFMPs detector and conducted experiments. The results confirmed that the 0.15 mm SFMPs could be successfully heated and detected.

Protecting Our Devices: The Future of HPCF Quality Control

The development of this 400 kHz SiC-MOSFETs high-frequency-inverter-based SFMPs detector represents a significant step forward in ensuring the quality and safety of high-performance chemical films. By enabling the detection of even the smallest metal particles, this technology promises to reduce the risk of battery failures and improve the reliability of countless electronic devices. As our reliance on these devices continues to grow, innovations like this will play an increasingly vital role in safeguarding our technology and our lives.