To guarantee the secure and effective long-term functionality of lithium-ion batteries, vital functions, including lifespan estimation, condition assessment, and fault identification within battery management systems, are necessary. Battery impedance is a crucial indicator for assessing battery health and longevity, serving as an important reference in battery state evaluation. This study offers a comprehensive review of the characterization and applications of impedance spectroscopy. It highlights the increasing attention paid to broadband perturbation signals for impedance measurements, which promotes impedance characterization methods from laboratory to practical implementation. The impact of varying impedance characteristics on distinct cell states and their utilization is further examined. The discussion encompasses the challenges and opportunities for future research on onboard battery management system characterizations.