Abstract: To improve the low-temperature performance of batteries, the experiments of the chargedischarge characteristics of 80Ah Li-ion battery cell were conducted under the condition of cold temperature, and the wide-line metal film method for heating battery was presented.At-40 ℃, heating and discharge experiments had been performed on the battery cell.The experimental results show that the charge-discharge performance of battery cell is dropped substantially in cold climates, and the discharge performance can be significantly improved after heating by the wide-line metal film.Meanwhile, only increasing preheating-time can not greatly improve low-temperature performance of battery according to the contrast experiments.