 Abstract batteries are essential for achieving a carbon neutral world. However, due to their exothermic nature, careful monitoring of temperature and strain is necessary. To address this issue, customized optical sensors were developed and installed in a leion battery, lib. These sensors were able to measure temperature and radial strain in three different locations within the battery. It was found that the maximum temperature and radial strain variations occur in the center and at the end of the discharge step. This indicates that the internal heat generation and transfer of thermal energy processes lead to a concentration of heat in the lib's central region. Good feasibility and reproducibility were observed in the sensor's performance, which suggests that these sensors could be used to reduce the complexity and intrusiveness of battery safety parameters monitoring. This article was authored by Luca Sima Tuck, Pedro de Cabrita, Joao El Pinto, and others.