THz & Optical Frequency Comb Tech Prevents EV Battery Thermal Runaway

On July 28, 2026, researchers from KAIST in South Korea released a new non-destructive inspection solution combining terahertz waves and optical frequency combs for lithium battery production. It accurately detects nanoscale thickness irregularities on battery electrodes, which are the root cause of EV battery thermal runaway and fires. Slight unevenness of electrode thickness leads to uneven current flow during charging and discharging, creating concentrated hot spots that greatly raise fire risks for power batteries.

Traditional testing tools have obvious drawbacks for high-speed production lines. X-ray CT inspection delivers clear internal images but runs too slowly for mass manufacturing, while common laser sensors cannot penetrate electrode layers to capture real internal thickness data.

This new system adopts THz Fabry–Pérot interference, using an optical frequency comb as a high-precision reference. It can measure electrode thickness and refractive index in one scan without extra calibration. Its optimal detection resolution reaches 7.8 nm for anodes, and it works reliably even when electrodes tilt at 45 degrees, perfectly fitting automated battery assembly lines.

Apart from liquid lithium-ion batteries, the technology also supports quality control for all-solid-state batteries by catching tiny defects at early production stages, effectively improving finished battery safety and production yield. The relevant research has been published in the journal Nature Communications.

#fiber laser #THz #Optical frequency comb #laser source #non-destructive inspection