Distributed Fiber Optic Sensing to Assess In-Live Temperature Imaging Inside Batteries: Rayleigh and FBGs

As society bridges towards a sustainable and electrified future where batteries are the keystone, the challenge of improving their lifetime and reliability is of critical importance. Reaching such a target requires innovation in easily monitoring in-live physical and chemical parameters with spatial and temporal resolution. We previously injected multiplex optical fiber Bragg grating sensors (FBGs) in 18650 cells to provide cell temperature gradients under real working conditions. Herein, we show the feasibility of using Rayleigh back-scattering in a single-mode optical fiber as a sensor for temperature imaging of 18650 cell along its axial dimension with a millimetre-scale spatial resolution. This type of sensing offers interesting opportunities provided we can enhance its temperature resolution and simplify the data collecting and analysis parts.