Battery models are often applied to describe the dynamic characteristics of actual batteries and can be used to predict the state of the battery. Due to the process of charging and discharging, the battery heat generation will cause the inhomogeneity between battery inner temperature and surface temperature. In this paper, a novel battery impedance model, which takes the impact of the battery internal temperature gradient into account, is proposed to improve the battery model accuracy. Several experiments are designed and conducted for pouch battery to investigate the electrochemical impedance spectroscopy (EIS) characteristics with the artificial temperature gradient (using heating plate). Compared with the battery EIS results with the temperature homogeneity (equilibrated with the temperature chamber), it indicates that the battery internal temperature gradient will influence battery EIS regularly. Then the particle swarm optimization (PSO) is employed to identify the parameter of battery impedance model without temperature gradient to obtain the relationship between impedance and temperature. In order to obtain the more accurate parameter of battery impedance model with temperature gradient, the battery is discretized into several slices which are connected in parallel. The impedance of the entire battery will be calculated after the impedance of every slice is obtained. The results show that the calculated EIS from the battery model considering the temperature gradient show good accordance to the experimental values. In conclusion, the proposed battery model can be a valuable alternative for engineering application use.