The design of thermal management for lithium batteries requires fundamental parameters such as thermal conductivity, specific heat capacity, and heat transfer coefficient. Currently, there is no universal standard for measuring the thermal conductivity of individual battery cells. Zeal Instruments has developed a dual-state testing method, based on the non-contact temperature measurement principle of infrared thermography and a non-homogeneous heat transfer model assumption. This method, using a nonlinear inversion algorithm, allows for simultaneous determination of both longitudinal and radial thermal conductivity of the cell core, as well as the contact thermal resistance between the core and the casing, thereby addressing a technical gap in this testing field.