 The battery management system, BMS, is essential for ensuring the safety and reliability of electric and hybrid electric vehicles. It monitors the state of the battery, such as its charge level, health, and lifespan, and uses this information to adjust charging and discharging operations accordingly. However, there are still some challenges with existing BMSes, such as their ability to accurately assess the state of the battery. This paper reviews the latest methods used to evaluate the state of a battery and proposes potential solutions to address these challenges. This article was authored by Michael Pecht, Kwak-El Sui, Injiao Xing, and others.