Thermal Characterization of LiFePO 4 Cathode in Lithium Ion Cells

The thermal behavior of carbon-coated LiFePO4 cathode material was investigated using three different calorimetric techniques. Heat released during charge and discharge of cylindrical 18650 size cells was measured in an isothermal calorimeter. Accelerating rate calorimetry was used to investigate the cause of thermal runaway of the cylindrical 18650 size cells. On the other hand, differential scanning calorimeter was used to study the contribution of the delithiated carbon-coated LiFePO4 and the lithiated graphite to the overall thermal runaway through coin cells of 2032 size. The carbon-coated LiFePO4 showed very good thermal stability.