The interest in post-lithium batteries as an alternative to lithium-ion batteries boosted recently due to their substantial abundance, low cost, and sustainability. However, safety remains a critical barrier. With seven Accelerating Rate Calorimeters and extremely sensible Tian-Calvet calorimeters, the Battery Calorimeter Laboratory at the IAM-AWP of KIT offers the evaluation of thermodynamic, thermal and safety data for lithium-ion and post-lithium cells on material and cell level. Our holistic approach to ensure a safe upscaling of new battery technologies. In the framework of the highly competitive Excellence Strategy competition of the federation and the federal states of Germany, the POLiS (Post Lithium Storage) Cluster of Excellence was started at KIT and Ulm University in 2019 and recently the second 7-year funding period was granted. In POLiS reference sodium-ion pouch cells have been developed and also first commercial cylindrical sodium-ion cells in different formats are becoming available. Therefore, a comparative safety assessment of commercial 18650 cells and the POLiS reference cell has been performed. Two abuse methods were applied: thermal abuse using the heat-wait-seek test and mechanical abuse by nail penetration, both in an accelerating rate calorimeter (ARC). The critical parameters have been determined and compared for both types of cells. In addition, a cyclic ageing study has been performed on the commercial 18650 cells and the influence. This study investigated the influence of operating temperature (0°C, 25°C, and 40°C) and discharge rates (1C, 2C, and 3C) on the cyclic aging and the safety. The results together with post-mortem analysis using scanning electron microscopy reveal significant correlations between operating temperature, discharge rates, and safety parameters such as sodium plating and exothermic reactions, and self-heating rates. Insights from this study provide valuable guidance for optimizing the temperature management strategies of sodium-ion battery systems to enhance their longevity and safety in applications.