ISO 18300 is a test specification for the use of lithium-ion battery systems in combination with lead-acid batteries or capacitors in electric vehicles. This standard applies to automotive applications in class A voltage systems and specifies the test methods and performance requirements when lithium-ion battery systems are combined with lead-acid batteries or double-decked capacitors. The test content includes electrical performance, Mechanical Properties, environmental adaptability and safety assessment, designed to ensure the compatibility, Reliability and safety of battery systems. The standard applies only to combinations of energy storage systems integrated in the same housing, providing a unified test basis for electric vehicle manufacturers and battery suppliers.