ELECTROTHERMAL MODELING OF POLYMER LITHIUM BATTERIES FOR STARTING PERIOD AND PULSE POWER

Since power capabilities of solid polymer lithium batteries can only b e delivered above 60 degrees C, the thermal management in electric-veh icle applications has to be carefully considered. Electro-thermal mode lling of a thermally insulated 200 kg battery was performed, and elect rochemical data were obtained from laboratory cell impedance measureme nts at 20 and 80 degrees C. Starting at 20 degrees C as initial workin g temperature, the battery reaches 40 degrees C after 150 s of dischar ge in a 0.5 Omega resistance. At 40 degrees C, the useful peak power i s 20 kW. The energy expense for heating the battery from 20 to 40 degr ees C is 1.4 kWh, corresponding to 6% of the energy available in the b attery. After a stand-by period of 24 h, the temperature decreases fro m 80 to 50 degrees C, allowing efficient starting conditions.