Study on Low Temperature Characteristics and Heating Method of Lithium Battery for Vehicle

In the process of electric vehicle promotion, the range, charging time and safety are mainly restricted by the characteristics of power battery. The characteristics of lithium ion power battery are significantly affected by ambient temperature, especially in low temperature environment, its available energy and power attenuation is more serious, and long-term low temperature environment will accelerate the aging of power battery and shorten service life. The development of lithium battery has entered a slow growth period in recent years after a rapid period. For high energy density lithium batteries, it should be used very carefully. A little carelessness, light will affect life, heavy may explode fire. Of all the conditions of use, voltage and temperature are the two most important related conditions. The use of lithium batteries at low temperature has poor performance, whether charging or discharging, and may have an impact on life. Under low temperature conditions, the performance of lithium battery will decline, such as prolonged charging time, reduced charge and discharge, smaller battery capacity and faster power loss, which will affect the driving mileage of new energy vehicles^[1]. The working temperature of conventional lithium ion battery is between-20°C∼60°C, but the performance of lithium battery will decrease and the discharge capacity will decrease after generally less than 0°C, so the working temperature of lithium ion battery performance is 0∼40°C. If the temperature drops to a certain extent, the lithium battery will even be unable to charge and discharge. (paper)