Evaluation of Saft Ultra High Power Lithium Ion Cells (VL5U)

Report No. ARL-TR-4731
Authors: Jan L. Allen, Jeff Wolfenstine, Kang Xu, Donald Porschet, Thomas Salem, Wesley Tipton, Wishvender Behl, Jeff Read, T. Richard Jow, and Sonya Gargies
Date/Pages: February 2009; 24 pages
Abstract: We evaluated Saft Ultra High Power (UHP) cells (Saft designation VL5U) to determine their rate capability, low temperature performance, storage, and cycle life. The energy and power density at 5 A (1C) were 45 Wh/kg and 55 W/kg, respectively; at 1000 A (200C) were 25 Wh/kg and 10 kW/kg, respectively; and at a 500 A rate, the energy densities were 35, 29, and 29 Wh/kg at 20, -20, and -40 ¿C, respectively, and the power densities were 4.3, 3.9, and 3.6 kW/kg, respectively. The VL5U showed a high rate of self-discharge (tested at 70 ¿C). Our cycling testing showed that high rate cycling degrades the cell faster than high temperature cycling, revealing significant self-heating at high rates of discharge. These results indicate the cell design is immature; further development will remediate the high self-discharge rates and the self-heating during high rate discharge. Pulse discharge testing using a capacitive load showed that, at an output voltage of 2 V, a pulsed current of 8750 A may be achieved. The minimum cell resistance from the pulse testing was measured to be about 0.23 m¿.
Distribution: Approved for public release
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Last Update / Reviewed: February 1, 2009