The potential and current density distribution on the electrodes of a lithium-polymer battery were studied by using the finite element method. The effect of the configuration of the electrodes such as the aspect ratio of the electrodes and the size and placing of current collecting tabs as well as the discharge rates on the battery performance was examined to enhance the uniformity of the utilization of the active material of electrodes. The results showed that the aspect ratio of the electrodes and the size and placing of current collecting tabs have a significant effect on the potential and current density distribution on the electrodes to influence the distribution of the depth of discharge on the electrodes, thus affecting the uniform utilization of the active material of electrodes.