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Lithion, a division of Yardney Technical Products, under a PRDA contract, has developed a true prismatic Lithium Ion battery to meet the stated performance criteria for the MARS 2001 Lander. The Lander battery requires compatibility with environments from -30°C to 50°C, a capacity at -20°C of 25 Ah at a C/2 rate, and a cycle life of greater than 200 cycles. To meet these requirements Lithion performed extensive research to optimize performance at low temperature. Specifically, the relationship between cell capacity at various temperatures and anode material particle size was characterized. In addition, the relationship between weight loading and cell capacity at various temperatures was characterized. Furthermore, as the low temperature performance of a battery is often greater than that of an individual cell experiments were run to characterize heat generation and heat flow in the Lithium Ion system.

Yardney Technical Products is developing a high energy density Li-ion cell tailored for NASA's Extravehicular Mobility Unit battery. The goal of the program is to develop a Li-ion technology which offers long storage and cycle life in a system which provides energy density and exercise performance comparable to the current 6.7kg Zn-AgO battery. The Zinc-Silver Oxide cells which are most commonly used in this application provide 400 Wh/l with a 32 cycle life at 26.6Ah and 1.55V with a rated wet life of 425 days. To improve the energy density of the Li-ion cells we have focused on improving the energy density of its components. In addition to using thin metal foil current collectors, the energy density of the cathode material was improved by utilizing a high capacity Co doped nickel oxide material. Further efforts have focused on developing a more energy dense carbonaceous anode material. The results of this effort are reviewed.

Lithium-ion batteries have proven to be intrinsically safe, capable of long cycle life and environmentally friendly. These batteries provide high energy density and a low rate of self-discharge. Yardney has developed 2, 3, 5 and 20Ah prismatic cell designs in both metal and lightweight plastic cases. Prismatic cells are more space efficient then cylindrical cells and require less expensive tooling for manufacture. For high-rate pulse-power applications, Yardney has developed a bipolar lithium-ion system which can deliver more than 3000 charge / discharge cycles of pulse-power and five-second pulses at current densities as high as 70mA/cm2. The present bipolar effort is focused on development of a 270V bipolar battery for Aerospace and Aircraft Applications.