 Lithium-ion batteries are widely recognized as the leading technology for electrochemical energy storage, with significant applications in the automotive industry and renewable energy grids. However, battery management systems need to estimate indicators like state of charge and state of health, which cannot be directly measured, using algorithms that employ mathematical models and basic measurements. This review provides a comprehensive examination of various models and estimation techniques for Li-ion battery monitoring, aiming to simplify the process for new applications development. This article was authored by Miguel Marti Florenses, Andrew Cecilia, and Ramon Costacastello.