Plasmonic Based Fibre Optic Sensors as an in-Situ Battery Diagnostic Technique

Abstract

Plasmonic based fibre optic sensing is a technique that enables measurements of the refractive index of an analyte via a metal coated fibre optic sensor. Fibre optics are well suited to take measurements from difficult to access or remote locations, and the technique of plasmonic based sensing has been used widely in biotechnology research. In this research we demonstrate the use of the plasmonic sensing technology as a diagnostics tool in lithium-ion batteries, a novel use of this sensing technology.Plasmonic based fibre optic sensors are placed inside li-ion pouch cells, allowing access to information from directly inside the system. Our research has shown multiple promising features, including a correlation of the optical signal with cell charge and discharge, detection of cell events such as phase transitions, and crucially that the presence of the sensor has negligible impact on the cell performance. This opens up the possibility of a new battery diagnostic technique, with the potential to aid cell research and characterisation, battery usage optimisation and early detection of cell failure modes such as lithium plating. Figure 1