ISO/TS 23625:2021 is a technical specification for lithium-ion batteries for small ships issued by the international standards organization (ISO). The standard provides terminology, classification, safety requirements, test methods and installation guidelines for lithium-ion batteries and their systems. It is applicable to lithium-ion battery systems with a capacity greater than 600Wh, for general electrical load of ships and/or electric propulsion systems. The standard also deals with requirements for battery management systems (BMS) to ensure the safety and Reliability of batteries during use. ISO/TS 23625:2021 is mainly aimed at manufacturers and battery installers. It provides internationally harmonized technical guidance for the selection and installation of lithium-ion battery systems for small ships.