<i>In-situ</i> optical fiber measurements of the temperature within a proton exchange membrane fuel cell

Effective heat management is essential for optimising PEM fuel cell performance. Despite the availability of numerical models to predict thermal behaviour, experimental data for validation is limited due to challenging conditions and complex geometry. To overcome this, Fiber Bragg Grating (FBG) sensors were used for in-situ temperature measurements. An FBG sensor was placed between Gas Diffusion Layers (GDL) at the cathode and calibrated with a thermocouple under non-operational conditions. A linear correlation was found, showing a 13.13°C increase between 0.32 and 1.4 A cm−2. A one-dimensional numerical model simulated temperature distribution, integrating experimental and theoretical data for heat sources and mass flow. Simulations with varied humidification levels indicated that the scenario with 10 water molecules per sulfonic group in the membrane closely matched experimental results. This FBG sensor temperature detection method provides valuable insights for validating and refining thermal models in PEM fuel cells.