Advancing Measurement Capabilities in Lithium-Ion Batteries: Exploring the Potential of Fiber Optic Sensors for Thermal Monitoring of Battery Cells

TL;DR

This paper explores the use of fiber optic sensors, specifically OFDR and inert glass fibers, for detailed, real-time thermal monitoring inside lithium-ion batteries, offering a new approach to battery health assessment.

Contribution

It introduces a novel fiber optic measurement method for internal battery temperature monitoring, demonstrating high sensitivity, spatial resolution, and minimal interference with battery operation.

Findings

Sensors provide real-time temperature data along entire fiber length

Linear thermal response with high sensitivity in 0-80°C range

Preliminary validation shows compatibility with battery environments

Abstract

This work demonstrates the potential of fiber optic sensors for measuring thermal effects in lithium-ion batteries, using a fiber optic measurement method of Optical Frequency Domain Reflectometry (OFDR). The innovative application of fiber sensors allows for spatially resolved temperature measurement, particularly emphasizing the importance of monitoring not just the exterior but also the internal conditions within battery cells. Utilizing inert glass fibers as sensors, which exhibit minimal sensitivity to electric fields, opens up new pathways for their implementation in a wide range of applications, such as battery monitoring. The sensors used in this work provide real-time information along the entire length of the fiber, unlike commonly used Fiber Bragg Grating (FBG) sensors. It is shown that using the herein presented novel sensors in a temperature range of 0 to 80 degree celsius reveals a linear thermal dependency with high sensitivity and a local resolution of a few centimeters. Furthermore, this study presents preliminary findings on the potential application of fiber optic sensors in lithium-ion battery (LIB) cells, demonstrating that the steps required for battery integration do not impose any restrictive effects on thermal measurements.