The temperature inconsistency of lithium-ion battery due to the difference of location distribution and thermal management conditions will lead to the reduction of available energy and peak power of a series battery pack, but the quantitative influence relationship is not clear. Based on a second-order RC equivalent circuit model, in the temperature range of -20 ℃~25 ℃, this paper adopts the methods of temperature interpolation and interpolation fitting to obtain the battery discharge curve and peak current at any temperature, with errors of 2.19% and 6% at most respectively. This provides model support for the quantitative study of the impact of temperature inconsistency on the discharge performance of series battery packs. In order to quantitatively analyze the energy and power efficiency affected by temperature inconsistency, the energy and power utilization rates of a battery pack are defined, and 100 series batteries at different average temperatures and temperature differences are quantitatively simulated. The results show that the decrease of average temperature and the increase of temperature difference will increase the loss of battery energy and power. This provides a numerical reference for the temperature threshold control of battery thermal management.