Performance evaluation of Lithium Cobalt cells and the suitability for use in electric vehicles

Results of cycle testing and load testing 100 amp-hour prismatic lithium cobalt cells at -20degC, 0degC, +20degC and +40degC are presented. The goal was to demonstrate and / or confirm the name-plate capacity rating of the cell and to investigate the effect of cycling at various temperatures on capacity in the early life of the cell with the long term goal of using these cells in electric vehicles. Six cells were fully charged and discharged using a standard constant-current / constant-voltage regimen using the voltage limits recommended by the manufacturer. The cells were cycled 50 times over the course of approximately 12 - 13 days per cell at +20degC and five times each at -20degC, 0degC and +40degC. It was found that the cells would provide acceptable capacity and power at 0degC, +20degC and +40degC. The possibility of over discharging and self-overheating are discussed. A brief description of the requirements of an electric vehicle battery is given. The research was conducted at the Battery Evaluation Laboratory at UMass, Lowell in Lowell, Massachusetts, USA which is briefly described.