Lithium-ion batteries, retired from their first life in automotive field, can still retain 70% - 80% of their original capacity. Consequently, they could be repurposed for less demanding energy storage applications, delaying or eliminating the need for new systems. However, identifying suitable second-life applications is challenging and uncertain, as lithium-ion batteries passed through their first life, do not show the same thermal behaviour and heat production of a new battery, posing safety risks if not properly managed. This thesis focuses on high-fidelity evaluation of the thermal performance of a PHEV’s battery in second-life scenarios, using limited cell information and minimal experimental data.