Electrical and electrochemical performance characteristics of large capacity lithium-ion cells

We are currently evaluating large capacity (20-40 Ah) Bluestar (cylindrical ) and Yardney (prismatic) lithium-ion cells for their electrical and electr ochemical performance characteristics at different temperatures, The cell r esistances were nearly constant from room temperature down to -20 degrees C , but increased by over 10 times at -40 degrees C. The specific energies an d powers, as well as the energy densities and power densities are high and did not reach a plateau even at the highest discharge rates tested. For exa mple, the prismatic lithium-ion cells gave close to 280 Wh dm(-3) from a 4 A discharge and 249 Wh dm(-3) at 20 A, both at room temperature. For the sa me current range the specific energy values were 102 Wh kg(-1) and 91 Wh kg (-1). Cycle life and other electrical and electrochemical properties of the cells will be presented. (C) 1999 Elsevier Science S.A. All rights reserve d.