Simultaneous estimation of multiple thermal parameters of large-format laminated lithium-ion batteries

In-situ determination of the thermal parameters for lithium-ion batteries is important yet challenging. This paper presents and validates a method to simultaneously estimate multiple thermal parameters for large-format laminated lithium-ion batteries. In this method, a circular planar heater was attached at the center of the battery surface while the temperature responses at multiple strategically chosen locations were recorded with thermocouples. The heat conduction was modeled based on a two-dimensional axially-symmetric model containing heat capacity, thermal conductivities, and interfacial thermal conductance. These thermal parameters were tuned till the differences between the simulated and measured temperatures reached the minimum using optimization techniques. The estimated heat capacity agreed well with the result measured with an accelerating rate calorimeter. The proposed method can also be used to estimate the thermal parameters of other devices/structures consisting of a covering outside and heterogeneous materials inside.