High-resolution thermal monitoring of lithium-ion batteries using Brillouin scattering based fiber optic sensor with flexible spatial arrangement of sensing points

To ensure the safety assessment and reliable lifespan prediction of energy storage systems, an effective battery temperature management system is essential. Traditional point sensors with limited measurement ranges are inadequate for comprehensive diagnostics. This paper presents the Brillouin optical correlation domain analysis system as an innovative solution for real-time temperature distribution monitoring during battery operation. Our proposed distributed fiber optic sensor leverages advanced optical techniques to achieve spatial resolution of 1.4 cm and measurement uncertainty of 0.38 °C. For precise temperature distribution measurement on the surface of polymer-based lithium-ion batteries, a single strand of optical fiber was arranged in a serpentine pattern. We compared the temperature variations on the battery surface during different C-rates of charging and discharging processes using a traditional thermistor and our fiber optic sensor. The results confirm that the fiber optic sensor effectively captures sudden temperature changes due to its rapid response time. Furthermore, we demonstrated comprehensive temperature distribution monitoring during a 1C charge and discharge process, showcasing the capability of system in tracking thermal anomalies and accurately assessing the state of battery. This advanced monitoring approach significantly enhances battery health diagnostics and ensures better management of energy storage systems.