Estimating the State of Charge in Lithium Primary Batteries: Recent Advances and Critical Insights

Lithium primary batteries (LPBs) are widely used in various applications due to their high energy density and long shelf life, making the accurate estimation of their state of charge (SoC) critical for safety and reliability. This paper aims to provide recent advances and insights into SoC estimation techniques in LPBs. The methodology involves reviewing two conventional techniques: open-circuit voltage (OCV) measurement and Coulomb counting. While OCV methods face challenges due to minimal voltage changes across a wide SoC range, Coulomb counting, typically used in lithium-ion batteries (LIBs), is underutilized in LPBs. This review emphasizes the importance of proper SoC estimation not only for optimizing battery usage but also for minimizing environmental impacts by reducing unnecessary replacements. The findings underscore the need for improved SoC estimation methods in LPBs, particularly for applications where battery replacement is challenging. Overall, enhancing the understanding of SoC in LPBs can significantly contribute to the safety and effectiveness of essential devices powered by these batteries.