Energy and power characteristics of lithium-ion cells

We describe below the electrochemical performance characteristics of cylindrical (18 650) and prismatic (48.26×25.4×7.62) lithium-ion cells at ambient and sub-ambient temperatures. Ragone plots of power and energy data for these cells are compared, and indicate that at room temperature, the not, vert, similar500 mAh prismatic lithium-ion cells exhibit higher specific power and power density than the not, vert, similar1100 mAh cylindrical cells. Over the temperature range from 35 to −20°C, the cell impedance is almost constant for both cell types. These cells at 100% state-of-charge (s.o.c.) show very little voltage drop for current pulses up to 1 A.