Functional Safety Design and ISO26262 Compliance for BMS in EV and HEV

Abstract

The use of electric cars (HEV/PHEV/EV) is becoming the most widespread because for several good reasons. These vehicles employ batteries of different capacities. These batteries contain the potential of thermal runaway, posing a higher safety risk from thermal incidences. The Li-ion batteries should always operate within the safe operating area. Outside this range, undesirable chemical reactions may occur within the battery that can lead to excessive self-heating and even causes internal electrical shorts. Thermal runaway can be mitigated using electronic control systems, which are intended to maintain a safe state of the battery pack under all operating conditions. The battery management system ensures the product safety by monitoring temperature, current, and voltage. In this paper, the ISO26262 standard is applied to several example scenarios involving lithium-ion batteries for plug-in vehicles. The ISO26262 addresses the sector specific needs of electrical and electronics systems within road vehicles. Development and integration of automotive functionalities strengthen the need for functional safety and the need to provide evidence that functional safety objective is satisfied. Key concepts are explored in the paper and conclusions drawn regarding several of the standard's required processes, including hazard analysis and risk assessment, functional safety concept, functional safety and technical safety requirements, and related topics.