The article reviews the mechanisms of capacity fade in lithium-ion batteries, which occur due to unwanted side reactions such as electrolyte decomposition, passive film formation, and active material dissolution. These mechanisms are not currently included in existing mathematical models, which limits their predictive capability. The authors discuss the importance of understanding these processes for improving battery performance and safety. They also review various models of lithium-ion cells, highlighting the limitations of current models in capturing capacity fade. The article further examines the formation cycles, overcharge phenomena, and overcharge protection methods, emphasizing the need for more comprehensive models that account for these side reactions.The article reviews the mechanisms of capacity fade in lithium-ion batteries, which occur due to unwanted side reactions such as electrolyte decomposition, passive film formation, and active material dissolution. These mechanisms are not currently included in existing mathematical models, which limits their predictive capability. The authors discuss the importance of understanding these processes for improving battery performance and safety. They also review various models of lithium-ion cells, highlighting the limitations of current models in capturing capacity fade. The article further examines the formation cycles, overcharge phenomena, and overcharge protection methods, emphasizing the need for more comprehensive models that account for these side reactions.