Faseroptische Messtechniken zur ortsaufgelösten Temperaturmessung: innovative Methode zur Optimierung von Batteriesystemen und deren Überwachung

RWTH Publications (RWTH Aachen)

Abstract

Reliable monitoring of battery systems requires precise information about the condition of each individual cell. In practice, this is usually achieved only through model-based estimations relying on measurements of voltage, current and pointwise temperature. Since temperature distributions and material-specific changes within batteries are often highly inhomogeneous, such models reach their limits: local hotspots frequently remain undetected, while external influences can further distort the results. To overcome these limitations, this dissertation investigates the potential of fiber optic sensing based on Rayleigh-based coherent optical frequency domain reflectometry for high-resolution, spatially resolved temperature measurements in lithium-ion batteries. Optical fibers were integrated into prototype cells, which were then subjected to electrical, thermal and ageing tests. The results reveal a direct correlation between local temperature behavior, electrical cell performance and material-specific changes, all of which can be captured using the implemented sensor technology. This integration represents a novel in-cell measurement approach that enables the detection of internal processes without impairing cell functionality. Furthermore, the application of fiber optic sensing is demonstrated at the battery system level, allowing the early detection of local hotspots and thermal anomalies under realistic operating conditions. Overall, the results show that fiber optic sensors significantly enhance temperature monitoring and state assessment of battery systems, contributing substantially to improved performance, safety and service life.

Authors 1

1. Florian Patrick Linus Krause corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen