Novel hybrid cooling concept for battery thermal management design

Abstract

Electric vehicles (EVs) is one of the most promising solutions to global warming and fossil fuel crisis. The key to EV development is the battery. Li-ion battery has been the most popular choice in the industry for a variety of advantages over the others. However, battery performance is heavily related to its working temperature, and the health of battery a pack in long-term is hugely affected by temperature uniformity. The optimal working temperature ranges from 25°C to 40°C, while the temperature non-uniformity should be lower than 5°C. A novel hybrid cooling concept for battery applications is proposed and experimentally proved in this study. The concept utilizes any combination of conductive, convective, and evaporative phase change cooling effects. The concept takes nearly no extra power from a normal air cooling method by using capillary effect as the driving force of water coolant, but achieves a higher cooling efficiency and better temperature uniformity. The concept may recycle A/C condensate so the water coolant could be instantly consumed at its generation and hence adds no extra weight to the vehicle. The air and water coolant after use will be released to the ambient without harming the environment. The results show a higher cooling efficiency and better temperature uniformity over the pack. The concept was able to retain both of the maximum working temperature and non-uniformity under the limits.