Enhancing Safety of Power Supply Systems in Automotive Applications: Integrating Functional Safety (FuSa) and Safety of the Intended Functionality (SOTIF)

The automotive industry's development towards electrification and automation raises special attention to Safety-Related Availability (SaRA) of onboard power supply systems (powernets). This paper provides insights into the current state of safety development for powernets and highlights the challenges in the safety argumentation for batteries. Our key contributions are twofold: First, we synchronize FuSa and SOTIF safety processes to manage intricate interactions and enhance reusability. We present a case study demonstrating how this integrated process is applied to powernets. Second, we extend the application of SOTIF to low-level complex safety measures, such as battery diagnosis, as a supplement to the high-level functional safety concept. We further discuss the applicability of SOTIF to battery diagnosis and specifically focus on deriving acceptance criteria, identifying functional insufficiencies, defining triggering conditions, and comparing various validation methods. Despite the differences from AD/ADAS, SOTIF's goal to mitigate potential risks resulting from functional insufficiencies remains applicable to battery diagnosis. Finally, we propose a safety validation framework combining sensitivity analysis, probabilistic surrogate models, and importance sampling to provide quantitative safety argumentation. This paper primarily focuses on theoretical analysis and is intended to lay a robust theoretical foundation for power supply safety.