 The battery management system, BMS, in electric and hybrid electric vehicles ensures safe and reliable battery operation through state monitoring and evaluation, charge control, and cell balancing, but the uncertainty of a battery's performance under different operational and environmental conditions poses challenges to these functions. And this paper presents future concerns for BMSs and proposes possible solutions for state evaluation of batteries. This article was authored by Michael Pecht, Kwak-El Sui, Yin Zhou Xing, and others.