Yardney Technical Products has undertaken a program to develop large scale, 20 Ah size, lithium-ion cells for military and aerospace applications. A space efficient and adaptable parallel-plate prismatic design has been chosen for this program. Using advanced, energy dense materials, 20 Ah cells with a specific energy of 123 Wh/kg and energy density of 326 Wh/1 have been produced. Many of the design parameters for these cells were optimized using statistical design experiments with smaller test cells. These design experiments allowed the identification and optimization of important parameters in far less time than would have been required by standard, iterative, experimentation. Optimization of rate capability and extended life cycling were the primary objectives for these experiments. High discharge rates up to 2 C and extended, 100% DOD, life cycling to greater than 2000 cycles have been achieved.