New energy power battery thermal management

The thermal related issues of power batteries are the key factors that determine their performance, safety, life and cost.
    
  First, the temperature level of a lithium-ion battery directly affects its energy and power performance in use. When the temperature is low, the available capacity of the battery will rapidly decay. Charging the battery at an excessively low temperature (such as below 0 ° C) may cause an instantaneous voltage overcharge phenomenon, causing internal lithium evolution and further short circuit . Second, thermal issues related to lithium-ion batteries directly affect battery safety. Defects in the manufacturing process or improper operation during use may cause local overheating of the battery, and then cause a chain of exothermic reactions, eventually causing serious thermal runaway events such as smoke, fire, and even explosion, threatening the lives of vehicle drivers and passengers Safety. In addition, the operating or storage temperature of a lithium-ion battery affects its service life. The proper temperature of the battery is between 10 ~ 30 ° C. Too high or too low temperature will cause the battery life to decay faster. The large size of the power battery makes the ratio of its surface area to volume relatively small. The internal heat of the battery is not easy to dissipate, and the problems of uneven internal temperature and excessive local temperature rise are more likely. Total cost of ownership.
  
   The battery thermal management system is one of the key technologies to deal with the thermal related problems of the battery and ensure the performance, safety and life of the power battery. The main functions of the thermal management system include: 1) effective heat dissipation when the battery temperature is high to prevent thermal runaway accidents; 2) preheating when the battery temperature is low to increase the battery temperature and ensure charging and discharging performance at low temperatures And safety; 3) reduce the temperature difference within the battery pack, suppress the formation of local hot zones, prevent the battery from decaying too quickly at high temperature locations, and reduce the overall battery life.