This paper studies on the performance of lithium-ion batteries at different temperatures. The charging and discharging and EIS experiments were carried out to explain the poor performance of the batteries at low temperatures. Experimental results show that as the decrease of the temperatures, the voltage of the battery reached the cut-off voltage rapidly and internal resistance of battery increases apparently, especially polarization resistance. Moreover, voltage platform of discharge drops, performance of high discharge rate is seriously deteriorated. The capacity and impedance of lithium ion batteries are not recoverable by low temperature charging. Thus, electric cars should not be used at low temperatures and preheated before starting at cold winter. Introduction The increasingly serious environmental pollution makes more people emphasize on environmental protection. New energy vehicles (NEVs), as environmentally and friendly models are chosen to alternate traditional fuel vehicles. Lithium-ion battery with high power, energy and output voltage is chosen as power battery that is one of the three core technologies of NEVs. However, it also has many disadvantages such as high cost, thermal runaway and low temperature performance coupled to thermal effects. For examples, its electrochemical performance is extremely susceptible to ambient temperature. In the low temperature environment, the viscosity of the electrolyte increases, the electric charge moves slowly and the velocity of electrochemical reaction slows. In extreme cases, the electrolyte which is evenly frozen makes the battery discharge hardly so that the electric car cannot start successfully. In addition, the charging time becomes shorter and the charging capacity apparently decreased when the ambient temperature below zero degrees Celsius. If the battery in the low ambient temperature works for a long time, the battery life will be greatly reduced. Currently, the working range lithium ion battery is -20 degrees Celsius and 50 Celsius. But in actually use, most of the lithium-ion battery can only ensure the work performance above zero Celsius. Tippmann, S., et al [1]had done many experiments in which cells are charged under different operating conditions. Capacity fade is measured after a significant number of cycles and compared to the simulated anode potential. Charge capacity was identified as important parameter influencing degradation. S.S.Zhang[2] used electrochemical impedance spectroscopy (EIS) study cycling performance of battery cells in -60 Celsius and 0 Celsius. Results showed that In the fully charged and discharged states as well as at the low temperatures (≤20°C), the cell of the Li-ion cells is predominated, they explained two low temperature phenomena of the Li-ion battery: (1) Charging of a fully discharged cell is much more difficult than discharging of a fully charged cell, and (2) both the power (operating voltage) and energy (delivered capacity) are substantially reduced. Lei[3] had done the charge and discharge experiment at 20° C to-40°C environment, analyzed the relationship between temperature and the characteristics of charge-discharge, capacity, voltage, internal resistance and discharge power that were obtained by carrying static and dynamic testing on the lithium-ion batteries. The experimental results showed that: As temperature dropping, Lithium-ion battery discharge capacity and discharge voltage were reduced rapidly, constant current charging time was shortened greatly , constant current charge capacity was reduced. While the constant voltage charging time was extended, the total charge capacity was reduced. Yang[4] tested the charging 7th International Conference on Mechatronics, Computer and Education Informationization (MCEI 2017) Copyright © 2017, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Computer Science Research, volume 75