Low Complexity and High Safety Architecture of Automotive Li-ion Battery Management Systems in Compliance with the ISO 26262 Standard

Abstract

Over the years, Lithium-ion (Li-ion) batteries (BT) have been established as the most commonly used battery type in electric vehicles (EV) due to their competitive advantages against other BT types. However, several risks are associated with the Li-ion BTs and therefore major concerns over safety issues are raised. The Battery Management System (BMS) that supervises the BT operation plays a critical role not only for the battery (BT) safety but also for the whole vehicle performance and efficiency. Thus, a set of critical functional safety requirements that intends to maintain the BT system within safe operation boundaries are defined in the ISO 26262 standard. How-ever, the generally formed automotive safety integrity level (ASIL) that comprises all the potential hazardous events with respect to severity, probability, and controllability in accordance with the standard may increase the complexity of the EV-BT system implementation. Therefore, aim of this paper is to provide a novel functional safety architecture that disengages the safety requirements of the hardware with that of the software by simplifying and accelerating the EV's functional safety design. The proposed functional safety architecture utilizes existing BMS technologies of EVs and therefore, it can be applied to almost every automotive BMS and even those that are in operation.