Thermal analysis of lithium polymer electrolyte batteries is carried out to examine the relationship between battery thermal behaviour and design parameters. By studying the effect of stack size and cooling/insulating conditions on battery temperature under different discharge rates, information is obtained as to how to maintain operating temperature by designing proper cell stacks and choosing proper cooling/insulating systems. Moreover, temperature distributions within cell stacks for different cell designs, including different thickness of cell components and different current collector materials, are calculated so as to carry out cell structure optimization from a heat transfer point of view. Finally, thermal characteristics of lithium polymer electrolyte batteries based on different positive electrodes (eg V6O13, TiS2 and redox polymer) are discussed.