Electrical and thermal characteristics of lithium-ion cells

The 18650-type lithium-ion cells are characterized by a cell resistance of 130 mΩ capacity of 1.27 Ah at 25°C, and a mid-discharge voltage of 3.6 V. The capacity loss in the 72-hr stand test was 3.39 percent. The heat dissipation properties were determined using a radiative calorimeter. During charge, initial endothermic cooling and subsequent exothermic heating beyond 55-percent state of charge were observed. At C/2 rate of discharge (which is considered medium rate), the heat dissipated was 17 mW/cm³. The heat dissipation profile during discharge is also unique in the presence of a minimum that is different from that observed for Ni-Cd, Ni-MH, and Ni-H ₂ cells