Thermal analysis of Lithium-ion batteries: an experimental investigation

The performance and stability of secondary batteries depend on the working temperature of the cells. This paper describes a set of experimental tests carried out to better understand the thermal behavior of Lithium-ion batteries under load. Different types of batteries have been analyzed to check the influence of a number of parameters that characterize the cells. The generation of hot spots has been registered, their presence being independent of the cell geometry and size; instead, the battery’s history and age, appear the main factors in determining the onset of hot spots on the surface of the cell, with increases of more than 20-30 degrees with respect to the average surface temperature. Nickel Manganese Cobalt-oxide cells presented major problems from the thermal point of view, while new LiFePO4 cells could withstand charge/discharge rates well beyond the maximum allowed values with no signs of excessive heating.